644962093 has 2 divisors, whose sum is σ = 644962094. Its totient is φ = 644962092.

The previous prime is 644962057. The next prime is 644962127. The reversal of 644962093 is 390269446.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 338081769 + 306880324 = 18387^2 + 17518^2 .

It is a cyclic number.

It is not a de Polignac number, because 644962093 - 2¹³ = 644953901 is a prime.

It is a super-2 number, since 2×644962093² = 831952202813881298, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (644962013) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322481046 + 322481047.

It is an arithmetic number, because the mean of its divisors is an integer number (322481047).

Almost surely, 2^644962093 is an apocalyptic number.

It is an amenable number.

644962093 is a deficient number, since it is larger than the sum of its proper divisors (1).

644962093 is an equidigital number, since it uses as much as digits as its factorization.

644962093 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 279936, while the sum is 43.

The square root of 644962093 is about 25396.1038941016. The cubic root of 644962093 is about 863.9953332831.

The spelling of 644962093 in words is "six hundred forty-four million, nine hundred sixty-two thousand, ninety-three".