643879156 has 12 divisors (see below), whose sum is σ = 1145260900. Its totient is φ = 316661760.

The previous prime is 643879147. The next prime is 643879169. The reversal of 643879156 is 651978346.

It can be written as a sum of positive squares in 2 ways, for example, as 63840100 + 580039056 = 7990^2 + 24084^2 .

It is a hoax number, since the sum of its digits (49) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 1319181 + ... + 1319668.

Almost surely, 2^643879156 is an apocalyptic number.

It is an amenable number.

643879156 is a deficient number, since it is larger than the sum of its proper divisors (501381744).

643879156 is a wasteful number, since it uses less digits than its factorization.

643879156 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2638914 (or 2638912 counting only the distinct ones).

The product of its digits is 1088640, while the sum is 49.

The square root of 643879156 is about 25374.7740088459. The cubic root of 643879156 is about 863.5114926104.

The spelling of 643879156 in words is "six hundred forty-three million, eight hundred seventy-nine thousand, one hundred fifty-six".