23991565 has 16 divisors (see below), whose sum is σ = 31385088. Its totient is φ = 17499456.

The previous prime is 23991559. The next prime is 23991571. The reversal of 23991565 is 56519932.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (23991559) and next prime (23991571).

It is not a de Polignac number, because 23991565 - 2³ = 23991557 is a prime.

It is a super-2 number, since 2×23991565² = 1151190382298450, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3172 + ... + 7618.

It is an arithmetic number, because the mean of its divisors is an integer number (1961568).

Almost surely, 2^23991565 is an apocalyptic number.

It is an amenable number.

23991565 is a deficient number, since it is larger than the sum of its proper divisors (7393523).

23991565 is a wasteful number, since it uses less digits than its factorization.

23991565 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4548.

The product of its digits is 72900, while the sum is 40.

The square root of 23991565 is about 4898.1185163285. The cubic root of 23991565 is about 288.4161173931.

The spelling of 23991565 in words is "twenty-three million, nine hundred ninety-one thousand, five hundred sixty-five".