644723542 has 16 divisors (see below), whose sum is σ = 1018614960. Its totient is φ = 305206272.

The previous prime is 644723537. The next prime is 644723567. The reversal of 644723542 is 245327446.

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, 71478 + ... + 79990.

It is an arithmetic number, because the mean of its divisors is an integer number (63663435).

Almost surely, 2^644723542 is an apocalyptic number.

644723542 is a deficient number, since it is larger than the sum of its proper divisors (373891418).

644723542 is a wasteful number, since it uses less digits than its factorization.

644723542 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10527.

The product of its digits is 161280, while the sum is 37.

The square root of 644723542 is about 25391.4068535007. The cubic root of 644723542 is about 863.8887986671. Note that the first 3 decimals are identical.

The spelling of 644723542 in words is "six hundred forty-four million, seven hundred twenty-three thousand, five hundred forty-two".