644608494 has 24 divisors (see below), whose sum is σ = 1397126640. Its totient is φ = 214796448.

The previous prime is 644608493. The next prime is 644608507. The reversal of 644608494 is 494806446.

It is a super-2 number, since 2×644608494² = 831040221073896072, which contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644608493) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 85839 + ... + 93045.

It is an arithmetic number, because the mean of its divisors is an integer number (58213610).

Almost surely, 2^644608494 is an apocalyptic number.

644608494 is an abundant number, since it is smaller than the sum of its proper divisors (752518146).

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

644608494 is a wasteful number, since it uses less digits than its factorization.

644608494 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12184 (or 12181 counting only the distinct ones).

The product of its (nonzero) digits is 663552, while the sum is 45.

The square root of 644608494 is about 25389.1412615709. The cubic root of 644608494 is about 863.8374099274.

The spelling of 644608494 in words is "six hundred forty-four million, six hundred eight thousand, four hundred ninety-four".