31220021123 has 4 divisors (see below), whose sum is σ = 31222801848. Its totient is φ = 31217240400.

The previous prime is 31220021117. The next prime is 31220021177. The reversal of 31220021123 is 32112002213.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 32112002213 = 1291 ⋅24873743.

It is a cyclic number.

It is not a de Polignac number, because 31220021123 - 2¹⁸ = 31219758979 is a prime.

It is a super-2 number, since 2×31220021123² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (31220021923) 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, 1373453 + ... + 1395998.

It is an arithmetic number, because the mean of its divisors is an integer number (7805700462).

Almost surely, 2^31220021123 is an apocalyptic number.

31220021123 is a deficient number, since it is larger than the sum of its proper divisors (2780725).

31220021123 is a wasteful number, since it uses less digits than its factorization.

31220021123 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2780724.

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

Adding to 31220021123 its reverse (32112002213), we get a palindrome (63332023336).

The spelling of 31220021123 in words is "thirty-one billion, two hundred twenty million, twenty-one thousand, one hundred twenty-three".