25981680 has 80 divisors (see below), whose sum is σ = 83342880. Its totient is φ = 6687744.

The previous prime is 25981679. The next prime is 25981687. The reversal of 25981680 is 8618952.

It is a tau number, because it is divible by the number of its divisors (80).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (25981687) 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, 5094 + ... + 8826.

It is an arithmetic number, because the mean of its divisors is an integer number (1041786).

Almost surely, 2^25981680 is an apocalyptic number.

25981680 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 25981680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (41671440).

25981680 is an abundant number, since it is smaller than the sum of its proper divisors (57361200).

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

25981680 is a wasteful number, since it uses less digits than its factorization.

25981680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3778 (or 3772 counting only the distinct ones).

The product of its (nonzero) digits is 34560, while the sum is 39.

The square root of 25981680 is about 5097.2227732364. Note that the first 3 decimals coincide. The cubic root of 25981680 is about 296.1800098149.

It can be divided in two parts, 2598 and 1680, that added together give a triangular number (4278 = T₉₂).

The spelling of 25981680 in words is "twenty-five million, nine hundred eighty-one thousand, six hundred eighty".