25780440 has 128 divisors (see below), whose sum is σ = 90408960. Its totient is φ = 5758464.

The previous prime is 25780439. The next prime is 25780457. The reversal of 25780440 is 4408752.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 25780398 and 25780407.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 39154 + ... + 39806.

It is an arithmetic number, because the mean of its divisors is an integer number (706320).

Almost surely, 2^25780440 is an apocalyptic number.

25780440 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 25780440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (45204480).

25780440 is an abundant number, since it is smaller than the sum of its proper divisors (64628520).

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

25780440 is a wasteful number, since it uses less digits than its factorization.

25780440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 721 (or 717 counting only the distinct ones).

The product of its (nonzero) digits is 8960, while the sum is 30.

The square root of 25780440 is about 5077.4442389848. Note that the first 3 decimals coincide. The cubic root of 25780440 is about 295.4133437687.

The spelling of 25780440 in words is "twenty-five million, seven hundred eighty thousand, four hundred forty".