25621997 has 2 divisors, whose sum is σ = 25621998. Its totient is φ = 25621996.

The previous prime is 25621979. The next prime is 25622021. The reversal of 25621997 is 79912652.

Together with previous prime (25621979) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21353641 + 4268356 = 4621^2 + 2066^2 .

It is a cyclic number.

It is not a de Polignac number, because 25621997 - 2⁸ = 25621741 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (25621927) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12810998 + 12810999.

It is an arithmetic number, because the mean of its divisors is an integer number (12810999).

Almost surely, 2^25621997 is an apocalyptic number.

It is an amenable number.

25621997 is a deficient number, since it is larger than the sum of its proper divisors (1).

25621997 is an equidigital number, since it uses as much as digits as its factorization.

25621997 is an evil number, because the sum of its binary digits is even.

The product of its digits is 68040, while the sum is 41.

The square root of 25621997 is about 5061.8175589407. The cubic root of 25621997 is about 294.8069099342.

The spelling of 25621997 in words is "twenty-five million, six hundred twenty-one thousand, nine hundred ninety-seven".