623665321 has 2 divisors, whose sum is σ = 623665322. Its totient is φ = 623665320.

The previous prime is 623665319. The next prime is 623665331. The reversal of 623665321 is 123566326.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 607376025 + 16289296 = 24645^2 + 4036^2 .

It is a cyclic number.

It is not a de Polignac number, because 623665321 - 2¹ = 623665319 is a prime.

Together with 623665319, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (623665331) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 311832660 + 311832661.

It is an arithmetic number, because the mean of its divisors is an integer number (311832661).

Almost surely, 2^623665321 is an apocalyptic number.

It is an amenable number.

623665321 is a deficient number, since it is larger than the sum of its proper divisors (1).

623665321 is an equidigital number, since it uses as much as digits as its factorization.

623665321 is an evil number, because the sum of its binary digits is even.

The product of its digits is 38880, while the sum is 34.

The square root of 623665321 is about 24973.2921538190. The cubic root of 623665321 is about 854.3789345380.

The spelling of 623665321 in words is "six hundred twenty-three million, six hundred sixty-five thousand, three hundred twenty-one".