31220131011021 has 12 divisors (see below), whose sum is σ = 45106816721148. Its totient is φ = 20808310553664.

The previous prime is 31220131011019. The next prime is 31220131011023. The reversal of 31220131011021 is 12011013102213.

31220131011021 is a `hidden beast` number, since 3 + 1 + 220 + 1 + 310 + 110 + 21 = 666.

It is an interprime number because it is at equal distance from previous prime (31220131011019) and next prime (31220131011023).

It can be written as a sum of positive squares in 2 ways, for example, as 7490703717225 + 23729427293796 = 2736915^2 + 4871286^2 .

It is not a de Polignac number, because 31220131011021 - 2¹ = 31220131011019 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 31220131010985 and 31220131011003.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31220131011023) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 425804670 + ... + 425877983.

It is an arithmetic number, because the mean of its divisors is an integer number (3758901393429).

Almost surely, 2^{31220131011021} is an apocalyptic number.

It is an amenable number.

31220131011021 is a deficient number, since it is larger than the sum of its proper divisors (13886685710127).

31220131011021 is a wasteful number, since it uses less digits than its factorization.

31220131011021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 851686732 (or 851686729 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 18.

Adding to 31220131011021 its reverse (12011013102213), we get a palindrome (43231144113234).

The spelling of 31220131011021 in words is "thirty-one trillion, two hundred twenty billion, one hundred thirty-one million, eleven thousand, twenty-one".