640734955 has 16 divisors (see below), whose sum is σ = 887785920. Its totient is φ = 434829312.

The previous prime is 640734949. The next prime is 640734971. The reversal of 640734955 is 559437046.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-640734955 is a prime.

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, 90970 + ... + 97759.

It is an arithmetic number, because the mean of its divisors is an integer number (55486620).

Almost surely, 2^640734955 is an apocalyptic number.

640734955 is a deficient number, since it is larger than the sum of its proper divisors (247050965).

640734955 is a wasteful number, since it uses less digits than its factorization.

640734955 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 188838.

The product of its (nonzero) digits is 453600, while the sum is 43.

The square root of 640734955 is about 25312.7429371058. The cubic root of 640734955 is about 862.1036274338.

The spelling of 640734955 in words is "six hundred forty million, seven hundred thirty-four thousand, nine hundred fifty-five".