25051981 has 2 divisors, whose sum is σ = 25051982. Its totient is φ = 25051980.

The previous prime is 25051919. The next prime is 25052003. The reversal of 25051981 is 18915052.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16402500 + 8649481 = 4050^2 + 2941^2 .

It is a cyclic number.

It is not a de Polignac number, because 25051981 - 2⁹ = 25051469 is a prime.

It is a super-2 number, since 2×25051981² = 1255203504048722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (25051781) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12525990 + 12525991.

It is an arithmetic number, because the mean of its divisors is an integer number (12525991).

Almost surely, 2^25051981 is an apocalyptic number.

It is an amenable number.

25051981 is a deficient number, since it is larger than the sum of its proper divisors (1).

25051981 is an equidigital number, since it uses as much as digits as its factorization.

25051981 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3600, while the sum is 31.

The square root of 25051981 is about 5005.1954007811. The cubic root of 25051981 is about 292.6042913466.

The spelling of 25051981 in words is "twenty-five million, fifty-one thousand, nine hundred eighty-one".