25403981 has 2 divisors, whose sum is σ = 25403982. Its totient is φ = 25403980.

The previous prime is 25403977. The next prime is 25403993. The reversal of 25403981 is 18930452.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 22372900 + 3031081 = 4730^2 + 1741^2 .

It is a cyclic number.

It is not a de Polignac number, because 25403981 - 2² = 25403977 is a prime.

It is a super-2 number, since 2×25403981² = 1290724501296722, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (25403281) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12701990 + 12701991.

It is an arithmetic number, because the mean of its divisors is an integer number (12701991).

Almost surely, 2^25403981 is an apocalyptic number.

It is an amenable number.

25403981 is a deficient number, since it is larger than the sum of its proper divisors (1).

25403981 is an equidigital number, since it uses as much as digits as its factorization.

25403981 is an odious number, because the sum of its binary digits is odd.

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

The square root of 25403981 is about 5040.2362047825. The cubic root of 25403981 is about 293.9683623999.

The spelling of 25403981 in words is "twenty-five million, four hundred three thousand, nine hundred eighty-one".