25815997 has 4 divisors (see below), whose sum is σ = 26057376. Its totient is φ = 25574620.

The previous prime is 25815989. The next prime is 25816001. The reversal of 25815997 is 79951852.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 25815997 - 2³ = 25815989 is a prime.

It is a super-2 number, since 2×25815997² = 1332931402208018, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (25815967) 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, 120529 + ... + 120742.

It is an arithmetic number, because the mean of its divisors is an integer number (6514344).

Almost surely, 2^25815997 is an apocalyptic number.

It is an amenable number.

25815997 is a deficient number, since it is larger than the sum of its proper divisors (241379).

25815997 is a wasteful number, since it uses less digits than its factorization.

25815997 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 241378.

The product of its digits is 226800, while the sum is 46.

The square root of 25815997 is about 5080.9444988112. The cubic root of 25815997 is about 295.5490950958.

The spelling of 25815997 in words is "twenty-five million, eight hundred fifteen thousand, nine hundred ninety-seven".