31231021020 has 192 divisors, whose sum is σ = 91201904640. Its totient is φ = 7979212800.

The previous prime is 31231020949. The next prime is 31231021027. The reversal of 31231021020 is 2012013213.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31231021027) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 52665844 + ... + 52666436.

It is an arithmetic number, because the mean of its divisors is an integer number (475009920).

Almost surely, 2^31231021020 is an apocalyptic number.

31231021020 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 31231021020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (45600952320).

31231021020 is an abundant number, since it is smaller than the sum of its proper divisors (59970883620).

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

31231021020 is a wasteful number, since it uses less digits than its factorization.

31231021020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 996 (or 994 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 15.

Adding to 31231021020 its reverse (2012013213), we get a palindrome (33243034233).

The spelling of 31231021020 in words is "thirty-one billion, two hundred thirty-one million, twenty-one thousand, twenty".