25516561 has 8 divisors (see below), whose sum is σ = 29194560. Its totient is φ = 21846768.

The previous prime is 25516553. The next prime is 25516571. The reversal of 25516561 is 16561552.

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

It is a cyclic number.

It is not a de Polignac number, because 25516561 - 2³ = 25516553 is a prime.

It is a Duffinian number.

It is a nialpdrome in base 12.

It is not an unprimeable number, because it can be changed into a prime (25516511) 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, 7755 + ... + 10543.

It is an arithmetic number, because the mean of its divisors is an integer number (3649320).

Almost surely, 2^25516561 is an apocalyptic number.

It is an amenable number.

25516561 is a deficient number, since it is larger than the sum of its proper divisors (3677999).

25516561 is a wasteful number, since it uses less digits than its factorization.

25516561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4103.

The product of its digits is 9000, while the sum is 31.

The square root of 25516561 is about 5051.3919863737. The cubic root of 25516561 is about 294.4019714800.

The spelling of 25516561 in words is "twenty-five million, five hundred sixteen thousand, five hundred sixty-one".