23397991 has 2 divisors, whose sum is σ = 23397992. Its totient is φ = 23397990.

The previous prime is 23397973. The next prime is 23398019. The reversal of 23397991 is 19979332.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 23397991 - 2¹³ = 23389799 is a prime.

It is a super-3 number, since 3×23397991³ (a number of 23 digits) contains 333 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (23397091) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 11698995 + 11698996.

It is an arithmetic number, because the mean of its divisors is an integer number (11698996).

Almost surely, 2^23397991 is an apocalyptic number.

23397991 is a deficient number, since it is larger than the sum of its proper divisors (1).

23397991 is an equidigital number, since it uses as much as digits as its factorization.

23397991 is an evil number, because the sum of its binary digits is even.

The product of its digits is 91854, while the sum is 43.

The square root of 23397991 is about 4837.1469897037. The cubic root of 23397991 is about 286.0176648094.

It can be divided in two parts, 233 and 97991, that multiplied together give a triangular number (22831903 = T₆₇₅₇).

The spelling of 23397991 in words is "twenty-three million, three hundred ninety-seven thousand, nine hundred ninety-one".