646525440 has 240 divisors, whose sum is σ = 2443611456. Its totient is φ = 156672000.

The previous prime is 646525421. The next prime is 646525441. The reversal of 646525440 is 44525646.

646525440 is a `hidden beast` number, since 64 + 6 + 52 + 544 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (240).

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 = 646525395 and 646525404.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (646525441) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 252165 + ... + 254715.

Almost surely, 2^646525440 is an apocalyptic number.

646525440 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 646525440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1221805728).

646525440 is an abundant number, since it is smaller than the sum of its proper divisors (1797086016).

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

646525440 is a wasteful number, since it uses less digits than its factorization.

646525440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2591 (or 2572 counting only the distinct ones).

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

The square root of 646525440 is about 25426.8645334025. The cubic root of 646525440 is about 864.6928598704.

The spelling of 646525440 in words is "six hundred forty-six million, five hundred twenty-five thousand, four hundred forty".