31231311331211 has 4 divisors (see below), whose sum is σ = 32589194432592. Its totient is φ = 29873428229832.

The previous prime is 31231311331177. The next prime is 31231311331223. The reversal of 31231311331211 is 11213311313213.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31231311331211 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (31231311331291) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 678941550656 + ... + 678941550701.

It is an arithmetic number, because the mean of its divisors is an integer number (8147298608148).

Almost surely, 2^{31231311331211} is an apocalyptic number.

31231311331211 is a deficient number, since it is larger than the sum of its proper divisors (1357883101381).

31231311331211 is a wasteful number, since it uses less digits than its factorization.

31231311331211 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1357883101380.

The product of its digits is 972, while the sum is 26.

Adding to 31231311331211 its reverse (11213311313213), we get a palindrome (42444622644424).

The spelling of 31231311331211 in words is "thirty-one trillion, two hundred thirty-one billion, three hundred eleven million, three hundred thirty-one thousand, two hundred eleven".