21100121021220 has 96 divisors (see below), whose sum is σ = 61650061320960. Its totient is φ = 5381971499520.

The previous prime is 21100121021149. The next prime is 21100121021227. The reversal of 21100121021220 is 2212012100112.

It is a super-2 number, since 2×21100121021220² (a number of 27 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a self number, because there is not a number n which added to its sum of digits gives 21100121021220.

It is not an unprimeable number, because it can be changed into a prime (21100121021227) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 143475486 + ... + 143622474.

It is an arithmetic number, because the mean of its divisors is an integer number (642188138760).

Almost surely, 2^{21100121021220} is an apocalyptic number.

21100121021220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21100121021220 is an abundant number, since it is smaller than the sum of its proper divisors (40549940299740).

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

21100121021220 is a wasteful number, since it uses less digits than its factorization.

21100121021220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 251045 (or 251043 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 15.

Adding to 21100121021220 its reverse (2212012100112), we get a palindrome (23312133121332).

The spelling of 21100121021220 in words is "twenty-one trillion, one hundred billion, one hundred twenty-one million, twenty-one thousand, two hundred twenty".