644052331 has 4 divisors (see below), whose sum is σ = 693594832. Its totient is φ = 594509832.

The previous prime is 644052301. The next prime is 644052341. The reversal of 644052331 is 133250446.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 644052331 - 2¹¹ = 644050283 is a prime.

It is a super-2 number, since 2×644052331² = 829606810133067122, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 644052331.

It is not an unprimeable number, because it can be changed into a prime (644052301) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 24771231 + ... + 24771256.

It is an arithmetic number, because the mean of its divisors is an integer number (173398708).

Almost surely, 2^644052331 is an apocalyptic number.

644052331 is a deficient number, since it is larger than the sum of its proper divisors (49542501).

644052331 is a wasteful number, since it uses less digits than its factorization.

644052331 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 49542500.

The product of its (nonzero) digits is 8640, while the sum is 28.

The square root of 644052331 is about 25378.1861250957. The cubic root of 644052331 is about 863.5889011308.

The spelling of 644052331 in words is "six hundred forty-four million, fifty-two thousand, three hundred thirty-one".