644926942 has 16 divisors (see below), whose sum is σ = 1056125952. Its totient is φ = 292928920.

The previous prime is 644926901. The next prime is 644926957. The reversal of 644926942 is 249629446.

It is a junction number, because it is equal to n+sod(n) for n = 644926892 and 644926901.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 21123 + ... + 41665.

It is an arithmetic number, because the mean of its divisors is an integer number (66007872).

Almost surely, 2^644926942 is an apocalyptic number.

644926942 is a deficient number, since it is larger than the sum of its proper divisors (411199010).

644926942 is a wasteful number, since it uses less digits than its factorization.

644926942 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21983.

The product of its digits is 746496, while the sum is 46.

The square root of 644926942 is about 25395.4118296987. The cubic root of 644926942 is about 863.9796368300.

The spelling of 644926942 in words is "six hundred forty-four million, nine hundred twenty-six thousand, nine hundred forty-two".