21123113 has 4 divisors (see below), whose sum is σ = 23043408. Its totient is φ = 19202820.

The previous prime is 21123103. The next prime is 21123119. The reversal of 21123113 is 31132112.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21123113 - 2¹⁸ = 20860969 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21123119) 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, 960131 + ... + 960152.

It is an arithmetic number, because the mean of its divisors is an integer number (5760852).

Almost surely, 2^21123113 is an apocalyptic number.

It is an amenable number.

21123113 is a deficient number, since it is larger than the sum of its proper divisors (1920295).

21123113 is a wasteful number, since it uses less digits than its factorization.

21123113 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1920294.

The product of its digits is 36, while the sum is 14.

The square root of 21123113 is about 4595.9887945903. The cubic root of 21123113 is about 276.4305094345.

Adding to 21123113 its reverse (31132112), we get a palindrome (52255225).

It can be divided in two parts, 2112 and 3113, that added together give a palindrome (5225).

The spelling of 21123113 in words is "twenty-one million, one hundred twenty-three thousand, one hundred thirteen".