25561800420 has 96 divisors (see below), whose sum is σ = 77194107648. Its totient is φ = 6282711552.

The previous prime is 25561800401. The next prime is 25561800443. The reversal of 25561800420 is 2400816552.

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, 503857 + ... + 552263.

It is an arithmetic number, because the mean of its divisors is an integer number (804105288).

Almost surely, 2^25561800420 is an apocalyptic number.

25561800420 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 25561800420, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38597053824).

25561800420 is an abundant number, since it is smaller than the sum of its proper divisors (51632307228).

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

25561800420 is a wasteful number, since it uses less digits than its factorization.

25561800420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 49109 (or 49107 counting only the distinct ones).

The product of its (nonzero) digits is 19200, while the sum is 33.

The spelling of 25561800420 in words is "twenty-five billion, five hundred sixty-one million, eight hundred thousand, four hundred twenty".