623409991 has 2 divisors, whose sum is σ = 623409992. Its totient is φ = 623409990.

The previous prime is 623409953. The next prime is 623410027. The reversal of 623409991 is 199904326.

623409991 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 is a cyclic number.

It is not a de Polignac number, because 623409991 - 2⁷ = 623409863 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (623409901) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 311704995 + 311704996.

It is an arithmetic number, because the mean of its divisors is an integer number (311704996).

Almost surely, 2^623409991 is an apocalyptic number.

623409991 is a deficient number, since it is larger than the sum of its proper divisors (1).

623409991 is an equidigital number, since it uses as much as digits as its factorization.

623409991 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 104976, while the sum is 43.

The square root of 623409991 is about 24968.1795692037. The cubic root of 623409991 is about 854.2623237303.

The spelling of 623409991 in words is "six hundred twenty-three million, four hundred nine thousand, nine hundred ninety-one".