644718490 has 32 divisors (see below), whose sum is σ = 1253621376. Its totient is φ = 237314880.

The previous prime is 644718467. The next prime is 644718493. The reversal of 644718490 is 94817446.

It is a Smith number, since the sum of its digits (43) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is not an unprimeable number, because it can be changed into a prime (644718493) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 35539 + ... + 50521.

It is an arithmetic number, because the mean of its divisors is an integer number (39175668).

Almost surely, 2^644718490 is an apocalyptic number.

644718490 is a deficient number, since it is larger than the sum of its proper divisors (608902886).

644718490 is a wasteful number, since it uses less digits than its factorization.

644718490 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15334.

The product of its (nonzero) digits is 193536, while the sum is 43.

The square root of 644718490 is about 25391.3073708307. The cubic root of 644718490 is about 863.8865422076.

The spelling of 644718490 in words is "six hundred forty-four million, seven hundred eighteen thousand, four hundred ninety".