21121299980 has 24 divisors (see below), whose sum is σ = 48386978640. Its totient is φ = 7680472640.

The previous prime is 21121299949. The next prime is 21121300003. The reversal of 21121299980 is 8999212112.

It is a super-2 number, since 2×21121299980² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (44).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 48002735 + ... + 48003174.

It is an arithmetic number, because the mean of its divisors is an integer number (2016124110).

Almost surely, 2^21121299980 is an apocalyptic number.

21121299980 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21121299980 is an abundant number, since it is smaller than the sum of its proper divisors (27265678660).

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

21121299980 is a wasteful number, since it uses less digits than its factorization.

21121299980 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 96005929 (or 96005927 counting only the distinct ones).

The product of its (nonzero) digits is 46656, while the sum is 44.

The spelling of 21121299980 in words is "twenty-one billion, one hundred twenty-one million, two hundred ninety-nine thousand, nine hundred eighty".