25981540 has 24 divisors (see below), whose sum is σ = 58758840. Its totient is φ = 9593088.

The previous prime is 25981537. The next prime is 25981591. The reversal of 25981540 is 4518952.

It can be written as a sum of positive squares in 4 ways, for example, as 1597696 + 24383844 = 1264^2 + 4938^2 .

It is a junction number, because it is equal to n+sod(n) for n = 25981496 and 25981505.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 49705 + ... + 50224.

It is an arithmetic number, because the mean of its divisors is an integer number (2448285).

Almost surely, 2^25981540 is an apocalyptic number.

25981540 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

25981540 is an abundant number, since it is smaller than the sum of its proper divisors (32777300).

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

25981540 is a wasteful number, since it uses less digits than its factorization.

25981540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 99951 (or 99949 counting only the distinct ones).

The product of its (nonzero) digits is 14400, while the sum is 34.

The square root of 25981540 is about 5097.2090402494. The cubic root of 25981540 is about 296.1794778340.

The spelling of 25981540 in words is "twenty-five million, nine hundred eighty-one thousand, five hundred forty".