6445351440 has 640 divisors, whose sum is σ = 26091901440. Its totient is φ = 1463132160.

The previous prime is 6445351421. The next prime is 6445351459. The reversal of 6445351440 is 441535446.

6445351440 is a `hidden beast` number, since 64 + 45 + 3 + 514 + 40 = 666.

It is an interprime number because it is at equal distance from previous prime (6445351421) and next prime (6445351459).

It is a super-2 number, since 2×6445351440² = 83085110370220147200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 6445351395 and 6445351404.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 32717422 + ... + 32717618.

It is an arithmetic number, because the mean of its divisors is an integer number (40768596).

Almost surely, 2^6445351440 is an apocalyptic number.

6445351440 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 6445351440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (13045950720).

6445351440 is an abundant number, since it is smaller than the sum of its proper divisors (19646550000).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

6445351440 is a wasteful number, since it uses less digits than its factorization.

6445351440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 259 (or 235 counting only the distinct ones).

The product of its (nonzero) digits is 115200, while the sum is 36.

The square root of 6445351440 is about 80282.9461342818. The cubic root of 6445351440 is about 1861.0106890046.

Adding to 6445351440 its reverse (441535446), we get a palindrome (6886886886).

The spelling of 6445351440 in words is "six billion, four hundred forty-five million, three hundred fifty-one thousand, four hundred forty".