31221033221 has 16 divisors (see below), whose sum is σ = 37245671424. Its totient is φ = 25588338864.

The previous prime is 31221033191. The next prime is 31221033223. The reversal of 31221033221 is 12233012213.

It is a cyclic number.

It is not a de Polignac number, because 31221033221 - 2³⁰ = 30147291397 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 31221033193 and 31221033202.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31221033223) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 444320 + ... + 509766.

It is an arithmetic number, because the mean of its divisors is an integer number (2327854464).

Almost surely, 2^31221033221 is an apocalyptic number.

It is an amenable number.

31221033221 is a deficient number, since it is larger than the sum of its proper divisors (6024638203).

31221033221 is a wasteful number, since it uses less digits than its factorization.

31221033221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 68440.

The product of its (nonzero) digits is 432, while the sum is 20.

Adding to 31221033221 its reverse (12233012213), we get a palindrome (43454045434).

The spelling of 31221033221 in words is "thirty-one billion, two hundred twenty-one million, thirty-three thousand, two hundred twenty-one".