25161921 has 24 divisors (see below), whose sum is σ = 39914784. Its totient is φ = 15785280.

The previous prime is 25161911. The next prime is 25161943. The reversal of 25161921 is 12916152.

25161921 is a `hidden beast` number, since 25 + 1 + 619 + 21 = 666.

It is not a de Polignac number, because 25161921 - 2¹⁰ = 25160897 is a prime.

It is a hoax number, since the sum of its digits (27) coincides with the sum of the digits of its distinct prime factors.

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

It is not an unprimeable number, because it can be changed into a prime (25161901) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1086 + ... + 7176.

It is an arithmetic number, because the mean of its divisors is an integer number (1663116).

Almost surely, 2^25161921 is an apocalyptic number.

It is an amenable number.

25161921 is a deficient number, since it is larger than the sum of its proper divisors (14752863).

25161921 is an equidigital number, since it uses as much as digits as its factorization.

25161921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6123 (or 6111 counting only the distinct ones).

The product of its digits is 1080, while the sum is 27.

The square root of 25161921 is about 5016.1659661538. The cubic root of 25161921 is about 293.0316956397.

The spelling of 25161921 in words is "twenty-five million, one hundred sixty-one thousand, nine hundred twenty-one".