640766057400 has 768 divisors, whose sum is σ = 2639831040000. Its totient is φ = 139679147520.

The previous prime is 640766057369. The next prime is 640766057419. The reversal of 640766057400 is 4750667046.

It is a happy number.

640766057400 is a `hidden beast` number, since 6 + 4 + 0 + 76 + 6 + 0 + 574 + 0 + 0 = 666.

It is a super-2 number, since 2×640766057400² (a number of 24 digits) contains 22 as substring.

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 pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 364277721 + ... + 364279479.

It is an arithmetic number, because the mean of its divisors is an integer number (3437280000).

Almost surely, 2^640766057400 is an apocalyptic number.

640766057400 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 640766057400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1319915520000).

640766057400 is an abundant number, since it is smaller than the sum of its proper divisors (1999064982600).

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

640766057400 is a wasteful number, since it uses less digits than its factorization.

640766057400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2233 (or 2218 counting only the distinct ones).

The product of its (nonzero) digits is 846720, while the sum is 45.

The spelling of 640766057400 in words is "six hundred forty billion, seven hundred sixty-six million, fifty-seven thousand, four hundred".