25815861 has 8 divisors (see below), whose sum is σ = 38245760. Its totient is φ = 17210556.

The previous prime is 25815833. The next prime is 25815919. The reversal of 25815861 is 16851852.

It is not a de Polignac number, because 25815861 - 2⁷ = 25815733 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (25815161) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 478045 + ... + 478098.

It is an arithmetic number, because the mean of its divisors is an integer number (4780720).

Almost surely, 2^25815861 is an apocalyptic number.

It is an amenable number.

25815861 is a deficient number, since it is larger than the sum of its proper divisors (12429899).

25815861 is an equidigital number, since it uses as much as digits as its factorization.

25815861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 956152 (or 956146 counting only the distinct ones).

The product of its digits is 19200, while the sum is 36.

The square root of 25815861 is about 5080.9311154551. The cubic root of 25815861 is about 295.5485761056.

The spelling of 25815861 in words is "twenty-five million, eight hundred fifteen thousand, eight hundred sixty-one".