31121011221 has 32 divisors (see below), whose sum is σ = 44795520000. Its totient is φ = 19154838528.

The previous prime is 31121011219. The next prime is 31121011247. The reversal of 31121011221 is 12211012113.

It is not a de Polignac number, because 31121011221 - 2¹ = 31121011219 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 31121011221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31121019221) 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, 1086360 + ... + 1114638.

It is an arithmetic number, because the mean of its divisors is an integer number (1399860000).

Almost surely, 2^31121011221 is an apocalyptic number.

It is an amenable number.

31121011221 is a deficient number, since it is larger than the sum of its proper divisors (13674508779).

31121011221 is a wasteful number, since it uses less digits than its factorization.

31121011221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28793.

The product of its (nonzero) digits is 24, while the sum is 15.

Adding to 31121011221 its reverse (12211012113), we get a palindrome (43332023334).

The spelling of 31121011221 in words is "thirty-one billion, one hundred twenty-one million, eleven thousand, two hundred twenty-one".