21121313023 has 4 divisors (see below), whose sum is σ = 21208953568. Its totient is φ = 21033672480.

The previous prime is 21121312999. The next prime is 21121313027. The reversal of 21121313023 is 32031312112.

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

It is a cyclic number.

It is not a de Polignac number, because 21121313023 - 2⁵ = 21121312991 is a prime.

It is a super-2 number, since 2×21121313023² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21121313027) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 43819911 + ... + 43820392.

It is an arithmetic number, because the mean of its divisors is an integer number (5302238392).

Almost surely, 2^21121313023 is an apocalyptic number.

21121313023 is a deficient number, since it is larger than the sum of its proper divisors (87640545).

21121313023 is an equidigital number, since it uses as much as digits as its factorization.

21121313023 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 87640544.

The product of its (nonzero) digits is 216, while the sum is 19.

Adding to 21121313023 its reverse (32031312112), we get a palindrome (53152625135).

The spelling of 21121313023 in words is "twenty-one billion, one hundred twenty-one million, three hundred thirteen thousand, twenty-three".