25815985 has 16 divisors (see below), whose sum is σ = 33480720. Its totient is φ = 18996480.

The previous prime is 25815967. The next prime is 25815989. The reversal of 25815985 is 58951852.

It can be written as a sum of positive squares in 8 ways, for example, as 3272481 + 22543504 = 1809^2 + 4748^2 .

It is not a de Polignac number, because 25815985 - 2¹¹ = 25813937 is a prime.

It is not an unprimeable number, because it can be changed into a prime (25815989) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 24775 + ... + 25795.

It is an arithmetic number, because the mean of its divisors is an integer number (2092545).

Almost surely, 2^25815985 is an apocalyptic number.

It is an amenable number.

25815985 is a deficient number, since it is larger than the sum of its proper divisors (7664735).

25815985 is a wasteful number, since it uses less digits than its factorization.

25815985 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1428.

The product of its digits is 144000, while the sum is 43.

The square root of 25815985 is about 5080.9433179283. The cubic root of 25815985 is about 295.5490493027.

The spelling of 25815985 in words is "twenty-five million, eight hundred fifteen thousand, nine hundred eighty-five".