644674145 has 4 divisors (see below), whose sum is σ = 773608980. Its totient is φ = 515739312.

The previous prime is 644674117. The next prime is 644674157. The reversal of 644674145 is 541476446.

644674145 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 310076881 + 334597264 = 17609^2 + 18292^2 .

It is a cyclic number.

It is not a de Polignac number, because 644674145 - 2⁸ = 644673889 is a prime.

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, 64467410 + ... + 64467419.

It is an arithmetic number, because the mean of its divisors is an integer number (193402245).

Almost surely, 2^644674145 is an apocalyptic number.

It is an amenable number.

644674145 is a deficient number, since it is larger than the sum of its proper divisors (128934835).

644674145 is a wasteful number, since it uses less digits than its factorization.

644674145 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 128934834.

The product of its digits is 322560, while the sum is 41.

The square root of 644674145 is about 25390.4341238979. The cubic root of 644674145 is about 863.8667351509.

The spelling of 644674145 in words is "six hundred forty-four million, six hundred seventy-four thousand, one hundred forty-five".