644533464469 has 2 divisors, whose sum is σ = 644533464470. Its totient is φ = 644533464468.

The previous prime is 644533464371. The next prime is 644533464479. The reversal of 644533464469 is 964464335446.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 337270562500 + 307262901969 = 580750^2 + 554313^2 .

It is a cyclic number.

It is not a de Polignac number, because 644533464469 - 2³³ = 635943529877 is a prime.

It is a super-2 number, since 2×644533464469² (a number of 24 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (644533464479) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322266732234 + 322266732235.

It is an arithmetic number, because the mean of its divisors is an integer number (322266732235).

Almost surely, 2^644533464469 is an apocalyptic number.

It is an amenable number.

644533464469 is a deficient number, since it is larger than the sum of its proper divisors (1).

644533464469 is an equidigital number, since it uses as much as digits as its factorization.

644533464469 is an evil number, because the sum of its binary digits is even.

The product of its digits is 89579520, while the sum is 58.

The spelling of 644533464469 in words is "six hundred forty-four billion, five hundred thirty-three million, four hundred sixty-four thousand, four hundred sixty-nine".