640663552 has 30 divisors (see below), whose sum is σ = 1281320768. Its totient is φ = 320323584.

The previous prime is 640663537. The next prime is 640663567. The reversal of 640663552 is 255366046.

It is an interprime number because it is at equal distance from previous prime (640663537) and next prime (640663567).

It is a super-2 number, since 2×640663552² = 820899573722513408, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3168 + ... + 35935.

Almost surely, 2^640663552 is an apocalyptic number.

It is an amenable number.

640663552 is a deficient number, since it is larger than the sum of its proper divisors (640657216).

640663552 is an frugal number, since it uses more digits than its factorization.

640663552 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39131 (or 39105 counting only the distinct ones).

The product of its (nonzero) digits is 129600, while the sum is 37.

The square root of 640663552 is about 25311.3324817166. The cubic root of 640663552 is about 862.0716021938.

The spelling of 640663552 in words is "six hundred forty million, six hundred sixty-three thousand, five hundred fifty-two".