644400662027 has 2 divisors, whose sum is σ = 644400662028. Its totient is φ = 644400662026.

The previous prime is 644400661991. The next prime is 644400662041. The reversal of 644400662027 is 720266004446.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 644400662027 - 2¹² = 644400657931 is a prime.

It is not a weakly prime, because it can be changed into another prime (644400662077) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322200331013 + 322200331014.

It is an arithmetic number, because the mean of its divisors is an integer number (322200331014).

Almost surely, 2^644400662027 is an apocalyptic number.

644400662027 is a deficient number, since it is larger than the sum of its proper divisors (1).

644400662027 is an equidigital number, since it uses as much as digits as its factorization.

644400662027 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 387072, while the sum is 41.

The spelling of 644400662027 in words is "six hundred forty-four billion, four hundred million, six hundred sixty-two thousand, twenty-seven".