25643780 has 24 divisors (see below), whose sum is σ = 54613440. Its totient is φ = 10112480.

The previous prime is 25643773. The next prime is 25643791. The reversal of 25643780 is 8734652.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 25643780.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7610 + ... + 10449.

It is an arithmetic number, because the mean of its divisors is an integer number (2275560).

Almost surely, 2^25643780 is an apocalyptic number.

25643780 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

25643780 is an abundant number, since it is smaller than the sum of its proper divisors (28969660).

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

25643780 is a wasteful number, since it uses less digits than its factorization.

25643780 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18139 (or 18137 counting only the distinct ones).

The product of its (nonzero) digits is 40320, while the sum is 35.

The square root of 25643780 is about 5063.9687992720. The cubic root of 25643780 is about 294.8904313957.

The spelling of 25643780 in words is "twenty-five million, six hundred forty-three thousand, seven hundred eighty".