25521613 has 4 divisors (see below), whose sum is σ = 27484828. Its totient is φ = 23558400.

The previous prime is 25521583. The next prime is 25521619. The reversal of 25521613 is 31612552.

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 17330569 + 8191044 = 4163^2 + 2862^2 .

It is a cyclic number.

It is not a de Polignac number, because 25521613 - 2²¹ = 23424461 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (25521619) 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, 981588 + ... + 981613.

It is an arithmetic number, because the mean of its divisors is an integer number (6871207).

Almost surely, 2^25521613 is an apocalyptic number.

It is an amenable number.

25521613 is a deficient number, since it is larger than the sum of its proper divisors (1963215).

25521613 is a wasteful number, since it uses less digits than its factorization.

25521613 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1963214.

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

The square root of 25521613 is about 5051.8920218073. The cubic root of 25521613 is about 294.4213996547.

The spelling of 25521613 in words is "twenty-five million, five hundred twenty-one thousand, six hundred thirteen".