3645991440 has 640 divisors, whose sum is σ = 15715660800. Its totient is φ = 765904896.

The previous prime is 3645991439. The next prime is 3645991451. The reversal of 3645991440 is 441995463.

3645991440 is a `hidden beast` number, since 3 + 6 + 4 + 599 + 14 + 40 = 666.

It is a super-3 number, since 3×3645991440³ (a number of 30 digits) contains 333 as substring.

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

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 15921246 + ... + 15921474.

It is an arithmetic number, because the mean of its divisors is an integer number (24555720).

Almost surely, 2^3645991440 is an apocalyptic number.

3645991440 is a gapful number since it is divisible by the number (30) 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 3645991440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (7857830400).

3645991440 is an abundant number, since it is smaller than the sum of its proper divisors (12069669360).

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

3645991440 is a wasteful number, since it uses less digits than its factorization.

3645991440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 283 (or 259 counting only the distinct ones).

The product of its (nonzero) digits is 466560, while the sum is 45.

The square root of 3645991440 is about 60382.0456758464. The cubic root of 3645991440 is about 1539.1178733971.

The spelling of 3645991440 in words is "three billion, six hundred forty-five million, nine hundred ninety-one thousand, four hundred forty".