644242967 has 2 divisors, whose sum is σ = 644242968. Its totient is φ = 644242966.

The previous prime is 644242901. The next prime is 644242969. The reversal of 644242967 is 769242446.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 644242967 - 2¹⁶ = 644177431 is a prime.

Together with 644242969, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (644242969) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322121483 + 322121484.

It is an arithmetic number, because the mean of its divisors is an integer number (322121484).

Almost surely, 2^644242967 is an apocalyptic number.

644242967 is a deficient number, since it is larger than the sum of its proper divisors (1).

644242967 is an equidigital number, since it uses as much as digits as its factorization.

644242967 is an evil number, because the sum of its binary digits is even.

The product of its digits is 580608, while the sum is 44.

The square root of 644242967 is about 25381.9417499923. The cubic root of 644242967 is about 863.6740986037.

The spelling of 644242967 in words is "six hundred forty-four million, two hundred forty-two thousand, nine hundred sixty-seven".