25561620 has 72 divisors (see below), whose sum is σ = 88617984. Its totient is φ = 5842368.

The previous prime is 25561609. The next prime is 25561621. The reversal of 25561620 is 2616552.

25561620 is a `hidden beast` number, since 25 + 5 + 616 + 20 = 666.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (25561621) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 8884 + ... + 11403.

Almost surely, 2^25561620 is an apocalyptic number.

25561620 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

25561620 is an abundant number, since it is smaller than the sum of its proper divisors (63056364).

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

25561620 is a wasteful number, since it uses less digits than its factorization.

25561620 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20309 (or 20304 counting only the distinct ones).

The product of its (nonzero) digits is 3600, while the sum is 27.

The square root of 25561620 is about 5055.8500768911. The cubic root of 25561620 is about 294.5751617167.

The spelling of 25561620 in words is "twenty-five million, five hundred sixty-one thousand, six hundred twenty".