644542534 has 8 divisors (see below), whose sum is σ = 975849768. Its totient is φ = 319259280.

The previous prime is 644542513. The next prime is 644542571. The reversal of 644542534 is 435245446.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a junction number, because it is equal to n+sod(n) for n = 644542493 and 644542502.

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, 1505727 + ... + 1506154.

It is an arithmetic number, because the mean of its divisors is an integer number (121981221).

Almost surely, 2^644542534 is an apocalyptic number.

644542534 is a deficient number, since it is larger than the sum of its proper divisors (331307234).

644542534 is a wasteful number, since it uses less digits than its factorization.

644542534 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3011990.

The product of its digits is 230400, while the sum is 37.

The square root of 644542534 is about 25387.8422478162. The cubic root of 644542534 is about 863.8079446733.

The spelling of 644542534 in words is "six hundred forty-four million, five hundred forty-two thousand, five hundred thirty-four".