31233121220 has 48 divisors (see below), whose sum is σ = 77544311040. Its totient is φ = 10339238784.

The previous prime is 31233121211. The next prime is 31233121247. The reversal of 31233121220 is 2212133213.

It is a super-2 number, since 2×31233121220² (a number of 22 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a junction number, because it is equal to n+sod(n) for n = 31233121192 and 31233121201.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3842384 + ... + 3850503.

It is an arithmetic number, because the mean of its divisors is an integer number (1615506480).

Almost surely, 2^31233121220 is an apocalyptic number.

It is an amenable number.

31233121220 is an abundant number, since it is smaller than the sum of its proper divisors (46311189820).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

31233121220 is a wasteful number, since it uses less digits than its factorization.

31233121220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7692932 (or 7692930 counting only the distinct ones).

The product of its (nonzero) digits is 432, while the sum is 20.

Adding to 31233121220 its reverse (2212133213), we get a palindrome (33445254433).

The spelling of 31233121220 in words is "thirty-one billion, two hundred thirty-three million, one hundred twenty-one thousand, two hundred twenty".