643444156 has 12 divisors (see below), whose sum is σ = 1127421400. Its totient is φ = 321323760.

The previous prime is 643444129. The next prime is 643444181. The reversal of 643444156 is 651444346.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 95931 + ... + 102418.

Almost surely, 2^643444156 is an apocalyptic number.

It is an amenable number.

643444156 is a deficient number, since it is larger than the sum of its proper divisors (483977244).

643444156 is a wasteful number, since it uses less digits than its factorization.

643444156 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 199164 (or 199162 counting only the distinct ones).

The product of its digits is 138240, while the sum is 37.

The square root of 643444156 is about 25366.2010557356. The cubic root of 643444156 is about 863.3169881407.

The spelling of 643444156 in words is "six hundred forty-three million, four hundred forty-four thousand, one hundred fifty-six".