25641521 has 2 divisors, whose sum is σ = 25641522. Its totient is φ = 25641520.

The previous prime is 25641509. The next prime is 25641529. The reversal of 25641521 is 12514652.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 25391521 + 250000 = 5039^2 + 500^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-25641521 is a prime.

It is not a weakly prime, because it can be changed into another prime (25641529) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12820760 + 12820761.

It is an arithmetic number, because the mean of its divisors is an integer number (12820761).

Almost surely, 2^25641521 is an apocalyptic number.

It is an amenable number.

25641521 is a deficient number, since it is larger than the sum of its proper divisors (1).

25641521 is an equidigital number, since it uses as much as digits as its factorization.

25641521 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2400, while the sum is 26.

The square root of 25641521 is about 5063.7457479617. The cubic root of 25641521 is about 294.8817720243.

It can be divided in two parts, 25641 and 521, that added together give a palindrome (26162).

The spelling of 25641521 in words is "twenty-five million, six hundred forty-one thousand, five hundred twenty-one".