25520399 has 4 divisors (see below), whose sum is σ = 25541040. Its totient is φ = 25499760.

The previous prime is 25520381. The next prime is 25520419. The reversal of 25520399 is 99302552.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-25520399 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 (25520309) 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, 8339 + ... + 10980.

It is an arithmetic number, because the mean of its divisors is an integer number (6385260).

Almost surely, 2^25520399 is an apocalyptic number.

25520399 is a deficient number, since it is larger than the sum of its proper divisors (20641).

25520399 is a wasteful number, since it uses less digits than its factorization.

25520399 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20640.

The product of its (nonzero) digits is 24300, while the sum is 35.

The square root of 25520399 is about 5051.7718673749. The cubic root of 25520399 is about 294.4167312815.

The spelling of 25520399 in words is "twenty-five million, five hundred twenty thousand, three hundred ninety-nine".