21123022031 has 4 divisors (see below), whose sum is σ = 21124231200. Its totient is φ = 21121812864.

The previous prime is 21123022027. The next prime is 21123022043. The reversal of 21123022031 is 13022032112.

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 21123022031 - 2² = 21123022027 is a prime.

It is a super-2 number, since 2×21123022031² (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 (21123622031) 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, 577991 + ... + 613448.

It is an arithmetic number, because the mean of its divisors is an integer number (5281057800).

Almost surely, 2^21123022031 is an apocalyptic number.

21123022031 is a deficient number, since it is larger than the sum of its proper divisors (1209169).

21123022031 is a wasteful number, since it uses less digits than its factorization.

21123022031 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1209168.

The product of its (nonzero) digits is 144, while the sum is 17.

Adding to 21123022031 its reverse (13022032112), we get a palindrome (34145054143).

The spelling of 21123022031 in words is "twenty-one billion, one hundred twenty-three million, twenty-two thousand, thirty-one".