21125798380 has 24 divisors (see below), whose sum is σ = 44612028720. Its totient is φ = 8403109440.

The previous prime is 21125798359. The next prime is 21125798383. The reversal of 21125798380 is 8389752112.

It is a happy number.

It is a hoax number, since the sum of its digits (46) coincides with the sum of the digits of its distinct prime factors.

It is a self number, because there is not a number n which added to its sum of digits gives 21125798380.

It is not an unprimeable number, because it can be changed into a prime (21125798383) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2946951 + ... + 2954110.

It is an arithmetic number, because the mean of its divisors is an integer number (1858834530).

Almost surely, 2^21125798380 is an apocalyptic number.

21125798380 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21125798380 is an abundant number, since it is smaller than the sum of its proper divisors (23486230340).

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

21125798380 is a wasteful number, since it uses less digits than its factorization.

21125798380 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5901249 (or 5901247 counting only the distinct ones).

The product of its (nonzero) digits is 241920, while the sum is 46.

The spelling of 21125798380 in words is "twenty-one billion, one hundred twenty-five million, seven hundred ninety-eight thousand, three hundred eighty".