644530626961 has 8 divisors (see below), whose sum is σ = 694642625600. Its totient is φ = 594494731152.

The previous prime is 644530626917. The next prime is 644530626967. The reversal of 644530626961 is 169626035446.

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 644530626961 - 2⁹ = 644530626449 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 644530626899 and 644530626908.

It is not an unprimeable number, because it can be changed into a prime (644530626967) 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, 19008111 + ... + 19041988.

It is an arithmetic number, because the mean of its divisors is an integer number (86830328200).

Almost surely, 2^644530626961 is an apocalyptic number.

It is an amenable number.

644530626961 is a deficient number, since it is larger than the sum of its proper divisors (50111998639).

644530626961 is a wasteful number, since it uses less digits than its factorization.

644530626961 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 38051415.

The product of its (nonzero) digits is 5598720, while the sum is 52.

The spelling of 644530626961 in words is "six hundred forty-four billion, five hundred thirty million, six hundred twenty-six thousand, nine hundred sixty-one".