25521013 has 6 divisors (see below), whose sum is σ = 29687766. Its totient is φ = 21875112.

The previous prime is 25521011. The next prime is 25521043. The reversal of 25521013 is 31012552.

It can be written as a sum of positive squares in only one way, i.e., 15421329 + 10099684 = 3927^2 + 3178^2 .

It is not a de Polignac number, because 25521013 - 2¹ = 25521011 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 (25521011) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 260370 + ... + 260467.

It is an arithmetic number, because the mean of its divisors is an integer number (4947961).

Almost surely, 2^25521013 is an apocalyptic number.

It is an amenable number.

25521013 is a deficient number, since it is larger than the sum of its proper divisors (4166753).

25521013 is an equidigital number, since it uses as much as digits as its factorization.

25521013 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 520851 (or 520844 counting only the distinct ones).

The product of its (nonzero) digits is 300, while the sum is 19.

The square root of 25521013 is about 5051.8326377662. The cubic root of 25521013 is about 294.4190924047.

Adding to 25521013 its reverse (31012552), we get a palindrome (56533565).

The spelling of 25521013 in words is "twenty-five million, five hundred twenty-one thousand, thirteen".