25508561 has 8 divisors (see below), whose sum is σ = 27562920. Its totient is φ = 23467392.

The previous prime is 25508521. The next prime is 25508563. The reversal of 25508561 is 16580552.

It can be written as a sum of positive squares in 4 ways, for example, as 1547536 + 23961025 = 1244^2 + 4895^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 25508561 - 2¹⁴ = 25492177 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (25508563) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 935 + ... + 7203.

It is an arithmetic number, because the mean of its divisors is an integer number (3445365).

Almost surely, 2^25508561 is an apocalyptic number.

It is an amenable number.

25508561 is a deficient number, since it is larger than the sum of its proper divisors (2054359).

25508561 is a wasteful number, since it uses less digits than its factorization.

25508561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6595.

The product of its (nonzero) digits is 12000, while the sum is 32.

The square root of 25508561 is about 5050.6000633588. The cubic root of 25508561 is about 294.3712011116.

It can be divided in two parts, 2550 and 8561, that added together give a palindrome (11111).

The spelling of 25508561 in words is "twenty-five million, five hundred eight thousand, five hundred sixty-one".