31133221020 has 384 divisors, whose sum is σ = 111708979200. Its totient is φ = 7119187200.

The previous prime is 31133221003. The next prime is 31133221037. The reversal of 31133221020 is 2012233113.

31133221020 is a `hidden beast` number, since 311 + 3 + 322 + 10 + 20 = 666.

It is an interprime number because it is at equal distance from previous prime (31133221003) and next prime (31133221037).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 31133220984 and 31133221002.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 35099017 + ... + 35099903.

It is an arithmetic number, because the mean of its divisors is an integer number (290908800).

Almost surely, 2^31133221020 is an apocalyptic number.

31133221020 is a gapful number since it is divisible by the number (30) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 31133221020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (55854489600).

31133221020 is an abundant number, since it is smaller than the sum of its proper divisors (80575758180).

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

31133221020 is a wasteful number, since it uses less digits than its factorization.

31133221020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1246 (or 1238 counting only the distinct ones).

The product of its (nonzero) digits is 216, while the sum is 18.

Adding to 31133221020 its reverse (2012233113), we get a palindrome (33145454133).

The spelling of 31133221020 in words is "thirty-one billion, one hundred thirty-three million, two hundred twenty-one thousand, twenty".