25687661 has 2 divisors, whose sum is σ = 25687662. Its totient is φ = 25687660.

The previous prime is 25687631. The next prime is 25687679. The reversal of 25687661 is 16678652.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 23222761 + 2464900 = 4819^2 + 1570^2 .

It is a cyclic number.

It is not a de Polignac number, because 25687661 - 2¹⁰ = 25686637 is a prime.

It is a plaindrome in base 11.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (25687621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12843830 + 12843831.

It is an arithmetic number, because the mean of its divisors is an integer number (12843831).

Almost surely, 2^25687661 is an apocalyptic number.

It is an amenable number.

25687661 is a deficient number, since it is larger than the sum of its proper divisors (1).

25687661 is an equidigital number, since it uses as much as digits as its factorization.

25687661 is an evil number, because the sum of its binary digits is even.

The product of its digits is 120960, while the sum is 41.

The square root of 25687661 is about 5068.2996162421. The cubic root of 25687661 is about 295.0585386081.

Subtracting from 25687661 its reverse (16678652), we obtain a palindrome (9009009).

The spelling of 25687661 in words is "twenty-five million, six hundred eighty-seven thousand, six hundred sixty-one".