6398533440 has 560 divisors, whose sum is σ = 25976622672. Its totient is φ = 1481048064.

The previous prime is 6398533411. The next prime is 6398533459. The reversal of 6398533440 is 443358936.

6398533440 is a `hidden beast` number, since 639 + 8 + 5 + 3 + 3 + 4 + 4 + 0 = 666.

It can be written as a sum of positive squares in 8 ways, for example, as 994519296 + 5404014144 = 31536^2 + 73512^2 .

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 5727762 + ... + 5728878.

Almost surely, 2^6398533440 is an apocalyptic number.

6398533440 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 6398533440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (12988311336).

6398533440 is an abundant number, since it is smaller than the sum of its proper divisors (19578089232).

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

6398533440 is a wasteful number, since it uses less digits than its factorization.

6398533440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1176 (or 1157 counting only the distinct ones).

The product of its (nonzero) digits is 933120, while the sum is 45.

The square root of 6398533440 is about 79990.8334748426. The cubic root of 6398533440 is about 1856.4937066005.

The spelling of 6398533440 in words is "six billion, three hundred ninety-eight million, five hundred thirty-three thousand, four hundred forty".