644970290 has 16 divisors (see below), whose sum is σ = 1162361880. Its totient is φ = 257673600.

The previous prime is 644970289. The next prime is 644970311. The reversal of 644970290 is 92079446.

It can be written as a sum of positive squares in 4 ways, for example, as 545549449 + 99420841 = 23357^2 + 9971^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 30611 + ... + 47190.

Almost surely, 2^644970290 is an apocalyptic number.

644970290 is a deficient number, since it is larger than the sum of its proper divisors (517391590).

644970290 is a wasteful number, since it uses less digits than its factorization.

644970290 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 78637.

The product of its (nonzero) digits is 108864, while the sum is 41.

The square root of 644970290 is about 25396.2652766110. The cubic root of 644970290 is about 863.9989935188.

The spelling of 644970290 in words is "six hundred forty-four million, nine hundred seventy thousand, two hundred ninety".