25513981 has 2 divisors, whose sum is σ = 25513982. Its totient is φ = 25513980.

The previous prime is 25513973. The next prime is 25513987. The reversal of 25513981 is 18931552.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 23677956 + 1836025 = 4866^2 + 1355^2 .

It is a cyclic number.

It is not a de Polignac number, because 25513981 - 2³ = 25513973 is a prime.

It is a super-2 number, since 2×25513981² = 1301926452936722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (25513987) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12756990 + 12756991.

It is an arithmetic number, because the mean of its divisors is an integer number (12756991).

Almost surely, 2^25513981 is an apocalyptic number.

It is an amenable number.

25513981 is a deficient number, since it is larger than the sum of its proper divisors (1).

25513981 is an equidigital number, since it uses as much as digits as its factorization.

25513981 is an evil number, because the sum of its binary digits is even.

The product of its digits is 10800, while the sum is 34.

The square root of 25513981 is about 5051.1366047653. The cubic root of 25513981 is about 294.3920487389.

The spelling of 25513981 in words is "twenty-five million, five hundred thirteen thousand, nine hundred eighty-one".