21105522 has 24 divisors (see below), whose sum is σ = 47423376. Its totient is φ = 7035012.

The previous prime is 21105509. The next prime is 21105547. The reversal of 21105522 is 22550112.

21105522 is a `hidden beast` number, since 2 + 110 + 552 + 2 = 666.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 21105495 and 21105504.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 21228 + ... + 22199.

It is an arithmetic number, because the mean of its divisors is an integer number (1975974).

Almost surely, 2^21105522 is an apocalyptic number.

21105522 is an abundant number, since it is smaller than the sum of its proper divisors (26317854).

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

21105522 is an equidigital number, since it uses as much as digits as its factorization.

21105522 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 43444 (or 43432 counting only the distinct ones).

The product of its (nonzero) digits is 200, while the sum is 18.

The square root of 21105522 is about 4594.0746619967. The cubic root of 21105522 is about 276.3537524468.

Adding to 21105522 its reverse (22550112), we get a palindrome (43655634).

The spelling of 21105522 in words is "twenty-one million, one hundred five thousand, five hundred twenty-two".