23151991 has 2 divisors, whose sum is σ = 23151992. Its totient is φ = 23151990.

The previous prime is 23151983. The next prime is 23152033. The reversal of 23151991 is 19915132.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 23151991 - 2³ = 23151983 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (23151941) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 11575995 + 11575996.

It is an arithmetic number, because the mean of its divisors is an integer number (11575996).

Almost surely, 2^23151991 is an apocalyptic number.

23151991 is a deficient number, since it is larger than the sum of its proper divisors (1).

23151991 is an equidigital number, since it uses as much as digits as its factorization.

23151991 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2430, while the sum is 31.

The square root of 23151991 is about 4811.6515875529. The cubic root of 23151991 is about 285.0117610823.

It can be divided in two parts, 23151 and 991, that added together give a palindrome (24142).

The spelling of 23151991 in words is "twenty-three million, one hundred fifty-one thousand, nine hundred ninety-one".