640263732 has 24 divisors (see below), whose sum is σ = 1495133472. Its totient is φ = 213252000.

The previous prime is 640263731. The next prime is 640263761. The reversal of 640263732 is 237362046.

It is a junction number, because it is equal to n+sod(n) for n = 640263693 and 640263702.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640263731) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4894 + ... + 36117.

It is an arithmetic number, because the mean of its divisors is an integer number (62297228).

Almost surely, 2^640263732 is an apocalyptic number.

It is an amenable number.

640263732 is an abundant number, since it is smaller than the sum of its proper divisors (854869740).

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

640263732 is a wasteful number, since it uses less digits than its factorization.

640263732 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 42319 (or 42317 counting only the distinct ones).

The product of its (nonzero) digits is 36288, while the sum is 33.

The square root of 640263732 is about 25303.4332057925. The cubic root of 640263732 is about 861.8922333753.

The spelling of 640263732 in words is "six hundred forty million, two hundred sixty-three thousand, seven hundred thirty-two".