25661579 has 4 divisors (see below), whose sum is σ = 25819176. Its totient is φ = 25503984.

The previous prime is 25661569. The next prime is 25661611. The reversal of 25661579 is 97516652.

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 25661579 - 2⁴ = 25661563 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (25661569) 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 3 ways as a sum of consecutive naturals, for example, 78554 + ... + 78879.

It is an arithmetic number, because the mean of its divisors is an integer number (6454794).

Almost surely, 2^25661579 is an apocalyptic number.

25661579 is a deficient number, since it is larger than the sum of its proper divisors (157597).

25661579 is a wasteful number, since it uses less digits than its factorization.

25661579 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 157596.

The product of its digits is 113400, while the sum is 41.

The square root of 25661579 is about 5065.7259104693. The cubic root of 25661579 is about 294.9586421002.

The spelling of 25661579 in words is "twenty-five million, six hundred sixty-one thousand, five hundred seventy-nine".