31001021220 has 96 divisors (see below), whose sum is σ = 93509724672. Its totient is φ = 7628594688.

The previous prime is 31001021123. The next prime is 31001021221. The reversal of 31001021220 is 2212010013.

It is a super-2 number, since 2×31001021220² (a number of 22 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (12).

It is a junction number, because it is equal to n+sod(n) for n = 31001021196 and 31001021205.

It is not an unprimeable number, because it can be changed into a prime (31001021221) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 4600974 + ... + 4607706.

It is an arithmetic number, because the mean of its divisors is an integer number (974059632).

Almost surely, 2^31001021220 is an apocalyptic number.

31001021220 is a gapful number since it is divisible by the number (30) formed by its first and last digit.

It is an amenable number.

31001021220 is an abundant number, since it is smaller than the sum of its proper divisors (62508703452).

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

31001021220 is a wasteful number, since it uses less digits than its factorization.

31001021220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12661 (or 12659 counting only the distinct ones).

The product of its (nonzero) digits is 24, while the sum is 12.

Adding to 31001021220 its reverse (2212010013), we get a palindrome (33213031233).

The spelling of 31001021220 in words is "thirty-one billion, one million, twenty-one thousand, two hundred twenty".