644261452364625 has 32 divisors (see below), whose sum is σ = 1128474796575360. Its totient is φ = 325521575928000.

The previous prime is 644261452364611. The next prime is 644261452364687. The reversal of 644261452364625 is 526463254162446.

It is a happy number.

It is not a de Polignac number, because 644261452364625 - 2¹⁵ = 644261452331857 is a prime.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 45211322866 + ... + 45211337115.

It is an arithmetic number, because the mean of its divisors is an integer number (35264837392980).

Almost surely, 2^{644261452364625} is an apocalyptic number.

It is an amenable number.

644261452364625 is a deficient number, since it is larger than the sum of its proper divisors (484213344210735).

644261452364625 is a wasteful number, since it uses less digits than its factorization.

644261452364625 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 90422660018 (or 90422660008 counting only the distinct ones).

The product of its digits is 199065600, while the sum is 60.

The spelling of 644261452364625 in words is "six hundred forty-four trillion, two hundred sixty-one billion, four hundred fifty-two million, three hundred sixty-four thousand, six hundred twenty-five".