31011111221 has 8 divisors (see below), whose sum is σ = 32840440920. Its totient is φ = 29182353408.

The previous prime is 31011111211. The next prime is 31011111251. The reversal of 31011111221 is 12211111013.

It can be written as a sum of positive squares in 4 ways, for example, as 162052900 + 30849058321 = 12730^2 + 175639^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 31011111221 - 2¹⁴ = 31011094837 is a prime.

It is a super-2 number, since 2×31011111221² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 31011111196 and 31011111205.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31011111211) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 28706 + ... + 250691.

It is an arithmetic number, because the mean of its divisors is an integer number (4105055115).

Almost surely, 2^31011111221 is an apocalyptic number.

It is an amenable number.

31011111221 is a deficient number, since it is larger than the sum of its proper divisors (1829329699).

31011111221 is a wasteful number, since it uses less digits than its factorization.

31011111221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 285943.

The product of its (nonzero) digits is 12, while the sum is 14.

Adding to 31011111221 its reverse (12211111013), we get a palindrome (43222222234).

The spelling of 31011111221 in words is "thirty-one billion, eleven million, one hundred eleven thousand, two hundred twenty-one".