23991563 has 4 divisors (see below), whose sum is σ = 24444288. Its totient is φ = 23538840.

The previous prime is 23991559. The next prime is 23991571. The reversal of 23991563 is 36519932.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 23991563 - 2² = 23991559 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (23991263) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 226283 + ... + 226388.

It is an arithmetic number, because the mean of its divisors is an integer number (6111072).

Almost surely, 2^23991563 is an apocalyptic number.

23991563 is a deficient number, since it is larger than the sum of its proper divisors (452725).

23991563 is an equidigital number, since it uses as much as digits as its factorization.

23991563 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 452724.

The product of its digits is 43740, while the sum is 38.

The square root of 23991563 is about 4898.1183121685. The cubic root of 23991563 is about 288.4161093787.

The spelling of 23991563 in words is "twenty-three million, nine hundred ninety-one thousand, five hundred sixty-three".