644049644 has 12 divisors (see below), whose sum is σ = 1288099344. Its totient is φ = 276021264.

The previous prime is 644049617. The next prime is 644049671. The reversal of 644049644 is 446940446.

It is an interprime number because it is at equal distance from previous prime (644049617) and next prime (644049671).

644049644 is an admirable 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, 11500859 + ... + 11500914.

It is an arithmetic number, because the mean of its divisors is an integer number (107341612).

Almost surely, 2^644049644 is an apocalyptic number.

It is an amenable number.

644049644 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

644049644 is a wasteful number, since it uses less digits than its factorization.

644049644 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23001784 (or 23001782 counting only the distinct ones).

The product of its (nonzero) digits is 331776, while the sum is 41.

The square root of 644049644 is about 25378.1331858748. The cubic root of 644049644 is about 863.5877001587.

The spelling of 644049644 in words is "six hundred forty-four million, forty-nine thousand, six hundred forty-four".