640661512 has 32 divisors (see below), whose sum is σ = 1259982720. Its totient is φ = 305035200.

The previous prime is 640661501. The next prime is 640661519. The reversal of 640661512 is 215166046.

It is a super-2 number, since 2×640661512² = 820894345916252288, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (640661519) 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, 9114 + ... + 36937.

It is an arithmetic number, because the mean of its divisors is an integer number (39374460).

Almost surely, 2^640661512 is an apocalyptic number.

It is an amenable number.

640661512 is a deficient number, since it is larger than the sum of its proper divisors (619321208).

640661512 is a wasteful number, since it uses less digits than its factorization.

640661512 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 46141 (or 46137 counting only the distinct ones).

The product of its (nonzero) digits is 8640, while the sum is 31.

The square root of 640661512 is about 25311.2921835295. The cubic root of 640661512 is about 862.0706871905.

The spelling of 640661512 in words is "six hundred forty million, six hundred sixty-one thousand, five hundred twelve".