644241967 has 2 divisors, whose sum is σ = 644241968. Its totient is φ = 644241966.

The previous prime is 644241959. The next prime is 644241973. The reversal of 644241967 is 769142446.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 644241967 - 2³ = 644241959 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (644242967) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322120983 + 322120984.

It is an arithmetic number, because the mean of its divisors is an integer number (322120984).

Almost surely, 2^644241967 is an apocalyptic number.

644241967 is a deficient number, since it is larger than the sum of its proper divisors (1).

644241967 is an equidigital number, since it uses as much as digits as its factorization.

644241967 is an evil number, because the sum of its binary digits is even.

The product of its digits is 290304, while the sum is 43.

The square root of 644241967 is about 25381.9220509401. The cubic root of 644241967 is about 863.6736517358.

The spelling of 644241967 in words is "six hundred forty-four million, two hundred forty-one thousand, nine hundred sixty-seven".