643651144 has 64 divisors (see below), whose sum is σ = 1352332800. Its totient is φ = 285410304.

The previous prime is 643651121. The next prime is 643651181. The reversal of 643651144 is 441156346.

It is a Harshad number since it is a multiple of its sum of digits (34).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 575674 + ... + 576790.

It is an arithmetic number, because the mean of its divisors is an integer number (21130200).

Almost surely, 2^643651144 is an apocalyptic number.

It is an amenable number.

643651144 is an abundant number, since it is smaller than the sum of its proper divisors (708681656).

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

643651144 is a wasteful number, since it uses less digits than its factorization.

643651144 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1382 (or 1378 counting only the distinct ones).

The product of its digits is 34560, while the sum is 34.

The square root of 643651144 is about 25370.2807237129. The cubic root of 643651144 is about 863.4095510031.

The spelling of 643651144 in words is "six hundred forty-three million, six hundred fifty-one thousand, one hundred forty-four".