25646521 has 2 divisors, whose sum is σ = 25646522. Its totient is φ = 25646520.

The previous prime is 25646519. The next prime is 25646531. The reversal of 25646521 is 12564652.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15912121 + 9734400 = 3989^2 + 3120^2 .

It is a cyclic number.

It is not a de Polignac number, because 25646521 - 2¹ = 25646519 is a prime.

Together with 25646519, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (25646531) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12823260 + 12823261.

It is an arithmetic number, because the mean of its divisors is an integer number (12823261).

Almost surely, 2^25646521 is an apocalyptic number.

It is an amenable number.

25646521 is a deficient number, since it is larger than the sum of its proper divisors (1).

25646521 is an equidigital number, since it uses as much as digits as its factorization.

25646521 is an evil number, because the sum of its binary digits is even.

The product of its digits is 14400, while the sum is 31.

The square root of 25646521 is about 5064.2394295689. The cubic root of 25646521 is about 294.9009377235.

The spelling of 25646521 in words is "twenty-five million, six hundred forty-six thousand, five hundred twenty-one".