640267236 has 36 divisors (see below), whose sum is σ = 1849661632. Its totient is φ = 182933424.

The previous prime is 640267231. The next prime is 640267237. The reversal of 640267236 is 632762046.

It is a happy number.

640267236 is a `hidden beast` number, since 640 + 2 + 6 + 7 + 2 + 3 + 6 = 666.

640267236 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (36).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a self number, because there is not a number n which added to its sum of digits gives 640267236.

It is not an unprimeable number, because it can be changed into a prime (640267231) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1270120 + ... + 1270623.

Almost surely, 2^640267236 is an apocalyptic number.

It is an amenable number.

640267236 is an abundant number, since it is smaller than the sum of its proper divisors (1209394396).

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

640267236 is a wasteful number, since it uses less digits than its factorization.

640267236 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2540760 (or 2540755 counting only the distinct ones).

The product of its (nonzero) digits is 72576, while the sum is 36.

The square root of 640267236 is about 25303.5024453138. The cubic root of 640267236 is about 861.8938056778.

The spelling of 640267236 in words is "six hundred forty million, two hundred sixty-seven thousand, two hundred thirty-six".