644509494 has 16 divisors (see below), whose sum is σ = 1432243440. Its totient is φ = 214836480.

The previous prime is 644509487. The next prime is 644509511. The reversal of 644509494 is 494905446.

It is a super-2 number, since 2×644509494² = 830784975712272072, which contains 22 as substring.

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, 5967627 + ... + 5967734.

It is an arithmetic number, because the mean of its divisors is an integer number (89515215).

Almost surely, 2^644509494 is an apocalyptic number.

644509494 is an abundant number, since it is smaller than the sum of its proper divisors (787733946).

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

644509494 is a wasteful number, since it uses less digits than its factorization.

644509494 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11935372 (or 11935366 counting only the distinct ones).

The product of its (nonzero) digits is 622080, while the sum is 45.

The square root of 644509494 is about 25387.1915343151. The cubic root of 644509494 is about 863.7931844878.

The spelling of 644509494 in words is "six hundred forty-four million, five hundred nine thousand, four hundred ninety-four".