21055110 has 16 divisors (see below), whose sum is σ = 50532336. Its totient is φ = 5614688.

The previous prime is 21055087. The next prime is 21055123. The reversal of 21055110 is 1155012.

It is a super-2 number, since 2×21055110² = 886635314224200, which 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 21055110.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 350889 + ... + 350948.

It is an arithmetic number, because the mean of its divisors is an integer number (3158271).

Almost surely, 2^21055110 is an apocalyptic number.

21055110 is an abundant number, since it is smaller than the sum of its proper divisors (29477226).

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

21055110 is a wasteful number, since it uses less digits than its factorization.

21055110 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 701847.

The product of its (nonzero) digits is 50, while the sum is 15.

The square root of 21055110 is about 4588.5847491356. The cubic root of 21055110 is about 276.1335470069.

The spelling of 21055110 in words is "twenty-one million, fifty-five thousand, one hundred ten".