25981957 has 4 divisors (see below), whose sum is σ = 25994700. Its totient is φ = 25969216.

The previous prime is 25981931. The next prime is 25981961. The reversal of 25981957 is 75918952.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 21659716 + 4322241 = 4654^2 + 2079^2 .

It is a 3-Lehmer number, since φ(25981957) divides (25981957-1)³.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-25981957 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 (25981057) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2548 + ... + 7645.

It is an arithmetic number, because the mean of its divisors is an integer number (6498675).

Almost surely, 2^25981957 is an apocalyptic number.

25981957 is the 2549-th decagonal number.

It is an amenable number.

25981957 is a deficient number, since it is larger than the sum of its proper divisors (12743).

25981957 is a wasteful number, since it uses less digits than its factorization.

25981957 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12742.

The product of its digits is 226800, while the sum is 46.

The square root of 25981957 is about 5097.2499448232. The cubic root of 25981957 is about 296.1810623716.

The spelling of 25981957 in words is "twenty-five million, nine hundred eighty-one thousand, nine hundred fifty-seven".