623666921 has 2 divisors, whose sum is σ = 623666922. Its totient is φ = 623666920.

The previous prime is 623666899. The next prime is 623666929. The reversal of 623666921 is 129666326.

623666921 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 599025625 + 24641296 = 24475^2 + 4964^2 .

It is a cyclic number.

It is not a de Polignac number, because 623666921 - 2¹⁴ = 623650537 is a prime.

It is not a weakly prime, because it can be changed into another prime (623666929) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 311833460 + 311833461.

It is an arithmetic number, because the mean of its divisors is an integer number (311833461).

Almost surely, 2^623666921 is an apocalyptic number.

It is an amenable number.

623666921 is a deficient number, since it is larger than the sum of its proper divisors (1).

623666921 is an equidigital number, since it uses as much as digits as its factorization.

623666921 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 139968, while the sum is 41.

The square root of 623666921 is about 24973.3241880211. The cubic root of 623666921 is about 854.3796651676.

The spelling of 623666921 in words is "six hundred twenty-three million, six hundred sixty-six thousand, nine hundred twenty-one".