25421640 has 64 divisors (see below), whose sum is σ = 78140160. Its totient is φ = 6612480.

The previous prime is 25421633. The next prime is 25421657. The reversal of 25421640 is 4612452.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a self number, because there is not a number n which added to its sum of digits gives 25421640.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2337 + ... + 7503.

It is an arithmetic number, because the mean of its divisors is an integer number (1220940).

Almost surely, 2^25421640 is an apocalyptic number.

25421640 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 25421640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39070080).

25421640 is an abundant number, since it is smaller than the sum of its proper divisors (52718520).

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

25421640 is a wasteful number, since it uses less digits than its factorization.

25421640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5222 (or 5218 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 24.

The square root of 25421640 is about 5041.9877032773. The cubic root of 25421640 is about 294.0364617650.

The spelling of 25421640 in words is "twenty-five million, four hundred twenty-one thousand, six hundred forty".