405644308621 has 2 divisors, whose sum is σ = 405644308622. Its totient is φ = 405644308620.

The previous prime is 405644308579. The next prime is 405644308651. The reversal of 405644308621 is 126803446504.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 359370275625 + 46274032996 = 599475^2 + 215114^2 .

It is a cyclic number.

It is not a de Polignac number, because 405644308621 - 2⁹ = 405644308109 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (405644308651) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 202822154310 + 202822154311.

It is an arithmetic number, because the mean of its divisors is an integer number (202822154311).

Almost surely, 2^405644308621 is an apocalyptic number.

It is an amenable number.

405644308621 is a deficient number, since it is larger than the sum of its proper divisors (1).

405644308621 is an equidigital number, since it uses as much as digits as its factorization.

405644308621 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 552960, while the sum is 43.

The spelling of 405644308621 in words is "four hundred five billion, six hundred forty-four million, three hundred eight thousand, six hundred twenty-one".