23403991 has 12 divisors (see below), whose sum is σ = 26605992. Its totient is φ = 20462544.

The previous prime is 23403983. The next prime is 23404001. The reversal of 23403991 is 19930432.

It is not a de Polignac number, because 23403991 - 2³ = 23403983 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (23403691) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2200 + ... + 7186.

It is an arithmetic number, because the mean of its divisors is an integer number (2217166).

Almost surely, 2^23403991 is an apocalyptic number.

23403991 is a deficient number, since it is larger than the sum of its proper divisors (3202001).

23403991 is a wasteful number, since it uses less digits than its factorization.

23403991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5038 (or 5019 counting only the distinct ones).

The product of its (nonzero) digits is 5832, while the sum is 31.

The square root of 23403991 is about 4837.7671502461. The cubic root of 23403991 is about 286.0421107732.

The spelling of 23403991 in words is "twenty-three million, four hundred three thousand, nine hundred ninety-one".