31321223220 has 384 divisors, whose sum is σ = 107580211200. Its totient is φ = 6657251328.

The previous prime is 31321223203. The next prime is 31321223237. The reversal of 31321223220 is 2232212313.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (31321223203) and next prime (31321223237).

It is a Harshad number since it is a multiple of its sum of digits (21).

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, 41375082 + ... + 41375838.

It is an arithmetic number, because the mean of its divisors is an integer number (280156800).

Almost surely, 2^31321223220 is an apocalyptic number.

31321223220 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 31321223220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (53790105600).

31321223220 is an abundant number, since it is smaller than the sum of its proper divisors (76258987980).

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

31321223220 is a wasteful number, since it uses less digits than its factorization.

31321223220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 927 (or 925 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 21.

Adding to 31321223220 its reverse (2232212313), we get a palindrome (33553435533).

It can be divided in two parts, 31321 and 223220, that added together give a triangular number (254541 = T₇₁₃).

The spelling of 31321223220 in words is "thirty-one billion, three hundred twenty-one million, two hundred twenty-three thousand, two hundred twenty".