644739474 has 16 divisors (see below), whose sum is σ = 1295162208. Its totient is φ = 213965952.

The previous prime is 644739451. The next prime is 644739479. The reversal of 644739474 is 474937446.

It is a super-3 number, since 3×644739474³ (a number of 27 digits) contains 333 as substring.

It is not an unprimeable number, because it can be changed into a prime (644739479) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 235327 + ... + 238050.

It is an arithmetic number, because the mean of its divisors is an integer number (80947638).

Almost surely, 2^644739474 is an apocalyptic number.

644739474 is an abundant number, since it is smaller than the sum of its proper divisors (650422734).

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

644739474 is a wasteful number, since it uses less digits than its factorization.

644739474 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 473609.

The product of its digits is 2032128, while the sum is 48.

The square root of 644739474 is about 25391.7205797480. The cubic root of 644739474 is about 863.8959145662.

The spelling of 644739474 in words is "six hundred forty-four million, seven hundred thirty-nine thousand, four hundred seventy-four".