640455100 has 18 divisors (see below), whose sum is σ = 1389787784. Its totient is φ = 256182000.

The previous prime is 640455083. The next prime is 640455103. The reversal of 640455100 is 1554046.

It is a Harshad number since it is a multiple of its sum of digits (25).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640455103) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 3202176 + ... + 3202375.

Almost surely, 2^640455100 is an apocalyptic number.

It is an amenable number.

640455100 is an abundant number, since it is smaller than the sum of its proper divisors (749332684).

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

640455100 is a wasteful number, since it uses less digits than its factorization.

640455100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6404565 (or 6404558 counting only the distinct ones).

The product of its (nonzero) digits is 2400, while the sum is 25.

The square root of 640455100 is about 25307.2143864156. The cubic root of 640455100 is about 861.9780949532.

It can be divided in two parts, 6404 and 55100, that added together give a square (61504 = 248²).

The spelling of 640455100 in words is "six hundred forty million, four hundred fifty-five thousand, one hundred".