644012506654511 has 4 divisors (see below), whose sum is σ = 658989541693032. Its totient is φ = 629035471615992.

The previous prime is 644012506654499. The next prime is 644012506654513. The reversal of 644012506654511 is 115456605210446.

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

It is a cyclic number.

It is not a de Polignac number, because 644012506654511 - 2⁴⁶ = 573643762476847 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 644012506654511.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644012506654513) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7488517519196 + ... + 7488517519281.

It is an arithmetic number, because the mean of its divisors is an integer number (164747385423258).

Almost surely, 2^{644012506654511} is an apocalyptic number.

644012506654511 is a deficient number, since it is larger than the sum of its proper divisors (14977035038521).

644012506654511 is a wasteful number, since it uses less digits than its factorization.

644012506654511 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14977035038520.

The product of its (nonzero) digits is 3456000, while the sum is 50.

The spelling of 644012506654511 in words is "six hundred forty-four trillion, twelve billion, five hundred six million, six hundred fifty-four thousand, five hundred eleven".