21121122110100 has 144 divisors (see below), whose sum is σ = 61986488610816. Its totient is φ = 5551597296000.

The previous prime is 21121122110069. The next prime is 21121122110177. The reversal of 21121122110100 is 101122112112.

It is a happy number.

It is a super-2 number, since 2×21121122110100² (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 21121122110100.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 87443697 + ... + 87684903.

It is an arithmetic number, because the mean of its divisors is an integer number (430461726464).

Almost surely, 2^{21121122110100} is an apocalyptic number.

21121122110100 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 21121122110100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30993244305408).

21121122110100 is an abundant number, since it is smaller than the sum of its proper divisors (40865366500716).

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

21121122110100 is a wasteful number, since it uses less digits than its factorization.

21121122110100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 245406 (or 245399 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 15.

Adding to 21121122110100 its reverse (101122112112), we get a palindrome (21222244222212).

It can be divided in two parts, 21121 and 122110100, that added together give a palindrome (122131221).

The spelling of 21121122110100 in words is "twenty-one trillion, one hundred twenty-one billion, one hundred twenty-two million, one hundred ten thousand, one hundred".