640366155 has 80 divisors (see below), whose sum is σ = 1348722144. Its totient is φ = 286571520.

The previous prime is 640366127. The next prime is 640366169. The reversal of 640366155 is 551663046.

640366155 is a `hidden beast` number, since 6 + 4 + 0 + 36 + 615 + 5 = 666.

640366155 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 640366155 - 2⁹ = 640365643 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 52387 + ... + 63443.

Almost surely, 2^640366155 is an apocalyptic number.

640366155 is a gapful number since it is divisible by the number (65) formed by its first and last digit.

640366155 is an abundant number, since it is smaller than the sum of its proper divisors (708355989).

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

640366155 is a wasteful number, since it uses less digits than its factorization.

640366155 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11098 (or 11089 counting only the distinct ones).

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

The square root of 640366155 is about 25305.4570201765. The cubic root of 640366155 is about 861.9381898965.

The spelling of 640366155 in words is "six hundred forty million, three hundred sixty-six thousand, one hundred fifty-five".