644970451 has 8 divisors (see below), whose sum is σ = 653972400. Its totient is φ = 636007680.

The previous prime is 644970437. The next prime is 644970479. The reversal of 644970451 is 154079446.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 644970451 - 2¹³ = 644962259 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (644970251) 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, 24171 + ... + 43291.

It is an arithmetic number, because the mean of its divisors is an integer number (81746550).

Almost surely, 2^644970451 is an apocalyptic number.

644970451 is a deficient number, since it is larger than the sum of its proper divisors (9001949).

644970451 is a wasteful number, since it uses less digits than its factorization.

644970451 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19589.

The product of its (nonzero) digits is 120960, while the sum is 40.

The square root of 644970451 is about 25396.2684463683. The cubic root of 644970451 is about 863.9990654104. Note that the first 3 decimals are identical.

The spelling of 644970451 in words is "six hundred forty-four million, nine hundred seventy thousand, four hundred fifty-one".