25188721 has 2 divisors, whose sum is σ = 25188722. Its totient is φ = 25188720.

The previous prime is 25188697. The next prime is 25188767. The reversal of 25188721 is 12788152.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15800625 + 9388096 = 3975^2 + 3064^2 .

It is a cyclic number.

It is not a de Polignac number, because 25188721 - 2⁵ = 25188689 is a prime.

It is not a weakly prime, because it can be changed into another prime (25188421) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12594360 + 12594361.

It is an arithmetic number, because the mean of its divisors is an integer number (12594361).

Almost surely, 2^25188721 is an apocalyptic number.

It is an amenable number.

25188721 is a deficient number, since it is larger than the sum of its proper divisors (1).

25188721 is an equidigital number, since it uses as much as digits as its factorization.

25188721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 8960, while the sum is 34.

The square root of 25188721 is about 5018.8366181815. The cubic root of 25188721 is about 293.1356948921.

The spelling of 25188721 in words is "twenty-five million, one hundred eighty-eight thousand, seven hundred twenty-one".