25623991 has 4 divisors (see below), whose sum is σ = 25682800. Its totient is φ = 25565184.

The previous prime is 25623973. The next prime is 25624007. The reversal of 25623991 is 19932652.

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 25623991 - 2¹⁷ = 25492919 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 25623991.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (25623911) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 28746 + ... + 29623.

It is an arithmetic number, because the mean of its divisors is an integer number (6420700).

Almost surely, 2^25623991 is an apocalyptic number.

25623991 is a deficient number, since it is larger than the sum of its proper divisors (58809).

25623991 is an equidigital number, since it uses as much as digits as its factorization.

25623991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 58808.

The product of its digits is 29160, while the sum is 37.

The square root of 25623991 is about 5062.0145199318. The cubic root of 25623991 is about 294.8145573960.

The spelling of 25623991 in words is "twenty-five million, six hundred twenty-three thousand, nine hundred ninety-one".