25523721 has 24 divisors (see below), whose sum is σ = 39550560. Its totient is φ = 16266888.

The previous prime is 25523713. The next prime is 25523723. The reversal of 25523721 is 12732552.

It is not a de Polignac number, because 25523721 - 2³ = 25523713 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (25523723) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 13390 + ... + 15176.

It is an arithmetic number, because the mean of its divisors is an integer number (1647940).

Almost surely, 2^25523721 is an apocalyptic number.

It is an amenable number.

25523721 is a deficient number, since it is larger than the sum of its proper divisors (14026839).

25523721 is a wasteful number, since it uses less digits than its factorization.

25523721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1842 (or 1813 counting only the distinct ones).

The product of its digits is 4200, while the sum is 27.

The square root of 25523721 is about 5052.1006522040. The cubic root of 25523721 is about 294.4295055063.

It can be divided in two parts, 25523 and 721, that added together give a square (26244 = 162²).

The spelling of 25523721 in words is "twenty-five million, five hundred twenty-three thousand, seven hundred twenty-one".