25009561 has 2 divisors, whose sum is σ = 25009562. Its totient is φ = 25009560.

The previous prime is 25009553. The next prime is 25009613. The reversal of 25009561 is 16590052.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 24950025 + 59536 = 4995^2 + 244^2 .

It is a cyclic number.

It is not a de Polignac number, because 25009561 - 2³ = 25009553 is a prime.

It is not a weakly prime, because it can be changed into another prime (25009511) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12504780 + 12504781.

It is an arithmetic number, because the mean of its divisors is an integer number (12504781).

Almost surely, 2^25009561 is an apocalyptic number.

It is an amenable number.

25009561 is a deficient number, since it is larger than the sum of its proper divisors (1).

25009561 is an equidigital number, since it uses as much as digits as its factorization.

25009561 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2700, while the sum is 28.

The square root of 25009561 is about 5000.9560086048. The cubic root of 25009561 is about 292.4390444486.

The spelling of 25009561 in words is "twenty-five million, nine thousand, five hundred sixty-one".