25613521 has 4 divisors (see below), whose sum is σ = 25655652. Its totient is φ = 25571392.

The previous prime is 25613507. The next prime is 25613527. The reversal of 25613521 is 12531652.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 8473921 + 17139600 = 2911^2 + 4140^2 .

It is a cyclic number.

It is not a de Polignac number, because 25613521 - 2⁹ = 25613009 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (25613527) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 20140 + ... + 21373.

It is an arithmetic number, because the mean of its divisors is an integer number (6413913).

Almost surely, 2^25613521 is an apocalyptic number.

It is an amenable number.

25613521 is a deficient number, since it is larger than the sum of its proper divisors (42131).

25613521 is an equidigital number, since it uses as much as digits as its factorization.

25613521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42130.

The product of its digits is 1800, while the sum is 25.

The square root of 25613521 is about 5060.9802410205. The cubic root of 25613521 is about 294.7743980401.

The spelling of 25613521 in words is "twenty-five million, six hundred thirteen thousand, five hundred twenty-one".