25139561 has 2 divisors, whose sum is σ = 25139562. Its totient is φ = 25139560.

The previous prime is 25139557. The next prime is 25139567. The reversal of 25139561 is 16593152.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 23232400 + 1907161 = 4820^2 + 1381^2 .

It is a cyclic number.

It is not a de Polignac number, because 25139561 - 2² = 25139557 is a prime.

It is not a weakly prime, because it can be changed into another prime (25139567) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12569780 + 12569781.

It is an arithmetic number, because the mean of its divisors is an integer number (12569781).

Almost surely, 2^25139561 is an apocalyptic number.

It is an amenable number.

25139561 is a deficient number, since it is larger than the sum of its proper divisors (1).

25139561 is an equidigital number, since it uses as much as digits as its factorization.

25139561 is an evil number, because the sum of its binary digits is even.

The product of its digits is 8100, while the sum is 32.

The square root of 25139561 is about 5013.9366769037. The cubic root of 25139561 is about 292.9448695911.

The spelling of 25139561 in words is "twenty-five million, one hundred thirty-nine thousand, five hundred sixty-one".