31111220321 has 16 divisors (see below), whose sum is σ = 32355313920. Its totient is φ = 29895315840.

The previous prime is 31111220317. The next prime is 31111220351. The reversal of 31111220321 is 12302211113.

It is a cyclic number.

It is not a de Polignac number, because 31111220321 - 2² = 31111220317 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 31111220321.

It is not an unprimeable number, because it can be changed into a prime (31111220351) 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, 829061 + ... + 865773.

It is an arithmetic number, because the mean of its divisors is an integer number (2022207120).

Almost surely, 2^31111220321 is an apocalyptic number.

It is an amenable number.

31111220321 is a deficient number, since it is larger than the sum of its proper divisors (1244093599).

31111220321 is a wasteful number, since it uses less digits than its factorization.

31111220321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 37096.

The product of its (nonzero) digits is 72, while the sum is 17.

Adding to 31111220321 its reverse (12302211113), we get a palindrome (43413431434).

The spelling of 31111220321 in words is "thirty-one billion, one hundred eleven million, two hundred twenty thousand, three hundred twenty-one".