640557209600 has 576 divisors, whose sum is σ = 2022800532480. Its totient is φ = 195349708800.

The previous prime is 640557209587. The next prime is 640557209651. The reversal of 640557209600 is 6902755046.

It is a Harshad number since it is a multiple of its sum of digits (44).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 185291072 + ... + 185294528.

It is an arithmetic number, because the mean of its divisors is an integer number (3511806480).

Almost surely, 2^640557209600 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 640557209600, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1011400266240).

640557209600 is an abundant number, since it is smaller than the sum of its proper divisors (1382243322880).

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

640557209600 is a wasteful number, since it uses less digits than its factorization.

640557209600 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3554 (or 3529 counting only the distinct ones).

The product of its (nonzero) digits is 453600, while the sum is 44.

The spelling of 640557209600 in words is "six hundred forty billion, five hundred fifty-seven million, two hundred nine thousand, six hundred".