21122113 has 4 divisors (see below), whose sum is σ = 21231748. Its totient is φ = 21012480.

The previous prime is 21122111. The next prime is 21122161. The reversal of 21122113 is 31122112.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 10837264 + 10284849 = 3292^2 + 3207^2 .

It is a cyclic number.

It is not a de Polignac number, because 21122113 - 2¹ = 21122111 is a prime.

It is a super-2 number, since 2×21122113² = 892287315169538, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21122093 and 21122102.

It is not an unprimeable number, because it can be changed into a prime (21122111) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 54528 + ... + 54913.

It is an arithmetic number, because the mean of its divisors is an integer number (5307937).

Almost surely, 2^21122113 is an apocalyptic number.

It is an amenable number.

21122113 is a deficient number, since it is larger than the sum of its proper divisors (109635).

21122113 is a wasteful number, since it uses less digits than its factorization.

21122113 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 109634.

The product of its digits is 24, while the sum is 13.

The square root of 21122113 is about 4595.8800027851. The cubic root of 21122113 is about 276.4261471533.

Adding to 21122113 its reverse (31122112), we get a palindrome (52244225).

Subtracting 21122113 from its reverse (31122112), we obtain a palindrome (9999999).

It can be divided in two parts, 2112 and 2113, that added together give a square (4225 = 65²).

The spelling of 21122113 in words is "twenty-one million, one hundred twenty-two thousand, one hundred thirteen".