644264111 has 2 divisors, whose sum is σ = 644264112. Its totient is φ = 644264110.

The previous prime is 644264099. The next prime is 644264191. The reversal of 644264111 is 111462446.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-644264111 is a prime.

It is a Sophie Germain prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (644264191) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322132055 + 322132056.

It is an arithmetic number, because the mean of its divisors is an integer number (322132056).

Almost surely, 2^644264111 is an apocalyptic number.

644264111 is a deficient number, since it is larger than the sum of its proper divisors (1).

644264111 is an equidigital number, since it uses as much as digits as its factorization.

644264111 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4608, while the sum is 29.

The square root of 644264111 is about 25382.3582631717. The cubic root of 644264111 is about 863.6835470708.

The spelling of 644264111 in words is "six hundred forty-four million, two hundred sixty-four thousand, one hundred eleven".