25821018 has 20 divisors (see below), whose sum is σ = 57858570. Its totient is φ = 8606952.

The previous prime is 25820989. The next prime is 25821043. The reversal of 25821018 is 81012852.

It can be written as a sum of positive squares in only one way, i.e., 16621929 + 9199089 = 4077^2 + 3033^2 .

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a junction number, because it is equal to n+sod(n) for n = 25820982 and 25821000.

It is an unprimeable number.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 79533 + ... + 79856.

Almost surely, 2^25821018 is an apocalyptic number.

25821018 is an abundant number, since it is smaller than the sum of its proper divisors (32037552).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

25821018 is a wasteful number, since it uses less digits than its factorization.

25821018 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 159403 (or 159394 counting only the distinct ones).

The product of its (nonzero) digits is 1280, while the sum is 27.

The square root of 25821018 is about 5081.4385758366. The cubic root of 25821018 is about 295.5682544800.

It can be divided in two parts, 2582 and 1018, that added together give a square (3600 = 60²).

The spelling of 25821018 in words is "twenty-five million, eight hundred twenty-one thousand, eighteen".