640493055 has 16 divisors (see below), whose sum is σ = 1138654560. Its totient is φ = 341596224.

The previous prime is 640493023. The next prime is 640493069. The reversal of 640493055 is 550394046.

It is a happy number.

640493055 is a `hidden beast` number, since 640 + 4 + 9 + 3 + 0 + 5 + 5 = 666.

It is not a de Polignac number, because 640493055 - 2⁵ = 640493023 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2372062 + ... + 2372331.

It is an arithmetic number, because the mean of its divisors is an integer number (71165910).

Almost surely, 2^640493055 is an apocalyptic number.

640493055 is a deficient number, since it is larger than the sum of its proper divisors (498161505).

640493055 is a wasteful number, since it uses less digits than its factorization.

640493055 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4744407 (or 4744401 counting only the distinct ones).

The product of its (nonzero) digits is 64800, while the sum is 36.

The square root of 640493055 is about 25307.9642602877. The cubic root of 640493055 is about 861.9951222891.

Subtracting from 640493055 its reverse (550394046), we obtain a palindrome (90099009).

The spelling of 640493055 in words is "six hundred forty million, four hundred ninety-three thousand, fifty-five".