644521274 has 8 divisors (see below), whose sum is σ = 968500800. Its totient is φ = 321687676.

The previous prime is 644521261. The next prime is 644521301. The reversal of 644521274 is 472125446.

It is a happy number.

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

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 285074 + ... + 287325.

It is an arithmetic number, because the mean of its divisors is an integer number (121062600).

Almost surely, 2^644521274 is an apocalyptic number.

644521274 is a deficient number, since it is larger than the sum of its proper divisors (323979526).

644521274 is a wasteful number, since it uses less digits than its factorization.

644521274 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 572964.

The product of its digits is 53760, while the sum is 35.

The square root of 644521274 is about 25387.4235400129. The cubic root of 644521274 is about 863.7984471057.

The spelling of 644521274 in words is "six hundred forty-four million, five hundred twenty-one thousand, two hundred seventy-four".