25831661 has 6 divisors (see below), whose sum is σ = 26550090. Its totient is φ = 25132176.

The previous prime is 25831643. The next prime is 25831667. The reversal of 25831661 is 16613852.

It is a happy number.

It can be written as a sum of positive squares in 3 ways, for example, as 21855625 + 3976036 = 4675^2 + 1994^2 .

It is not a de Polignac number, because 25831661 - 2¹⁴ = 25815277 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (25831667) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 8066 + ... + 10803.

It is an arithmetic number, because the mean of its divisors is an integer number (4425015).

Almost surely, 2^25831661 is an apocalyptic number.

It is an amenable number.

25831661 is a deficient number, since it is larger than the sum of its proper divisors (718429).

25831661 is an equidigital number, since it uses as much as digits as its factorization.

25831661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18943 (or 18906 counting only the distinct ones).

The product of its digits is 8640, while the sum is 32.

The square root of 25831661 is about 5082.4857107522. The cubic root of 25831661 is about 295.6088583635.

The spelling of 25831661 in words is "twenty-five million, eight hundred thirty-one thousand, six hundred sixty-one".