644601634 has 16 divisors (see below), whose sum is σ = 1012979520. Its totient is φ = 307054000.

The previous prime is 644601623. The next prime is 644601637. The reversal of 644601634 is 436106446.

It is a super-2 number, since 2×644601634² = 831022533110939912, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 644601634.

It is not an unprimeable number, because it can be changed into a prime (644601637) 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, 16369 + ... + 39460.

It is an arithmetic number, because the mean of its divisors is an integer number (63311220).

Almost surely, 2^644601634 is an apocalyptic number.

644601634 is a deficient number, since it is larger than the sum of its proper divisors (368377886).

644601634 is a wasteful number, since it uses less digits than its factorization.

644601634 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 56105.

The product of its (nonzero) digits is 41472, while the sum is 34.

The square root of 644601634 is about 25389.0061640861. The cubic root of 644601634 is about 863.8343455631.

The spelling of 644601634 in words is "six hundred forty-four million, six hundred one thousand, six hundred thirty-four".