21121110 has 48 divisors (see below), whose sum is σ = 55158480. Its totient is φ = 5607360.

The previous prime is 21121099. The next prime is 21121129. The reversal of 21121110 is 1112112.

It is a happy number.

It is a super-2 number, since 2×21121110² = 892202575264200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a junction number, because it is equal to n+sod(n) for n = 21121092 and 21121101.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 29436 + ... + 30144.

It is an arithmetic number, because the mean of its divisors is an integer number (1149135).

Almost surely, 2^21121110 is an apocalyptic number.

21121110 is an abundant number, since it is smaller than the sum of its proper divisors (34037370).

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

21121110 is a wasteful number, since it uses less digits than its factorization.

21121110 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1053 (or 1050 counting only the distinct ones).

The product of its (nonzero) digits is 4, while the sum is 9.

The square root of 21121110 is about 4595.7708820175. The cubic root of 21121110 is about 276.4217716470.

Adding to 21121110 its reverse (1112112), we get a palindrome (22233222).

It can be divided in two parts, 211 and 21110, that added together give a triangular number (21321 = T₂₀₆).

The spelling of 21121110 in words is "twenty-one million, one hundred twenty-one thousand, one hundred ten".