25516551 has 4 divisors (see below), whose sum is σ = 34022072. Its totient is φ = 17011032.

The previous prime is 25516537. The next prime is 25516553. The reversal of 25516551 is 15561552.

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

It is not a de Polignac number, because 25516551 - 2⁷ = 25516423 is a prime.

It is a Duffinian number.

It is a nialpdrome in base 12.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (25516553) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4252756 + ... + 4252761.

It is an arithmetic number, because the mean of its divisors is an integer number (8505518).

Almost surely, 2^25516551 is an apocalyptic number.

25516551 is a deficient number, since it is larger than the sum of its proper divisors (8505521).

25516551 is an equidigital number, since it uses as much as digits as its factorization.

25516551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8505520.

The product of its digits is 7500, while the sum is 30.

The square root of 25516551 is about 5051.3909965474. The cubic root of 25516551 is about 294.4019330211.

The spelling of 25516551 in words is "twenty-five million, five hundred sixteen thousand, five hundred fifty-one".