31031211817 has 4 divisors (see below), whose sum is σ = 32856577236. Its totient is φ = 29205846400.

The previous prime is 31031211793. The next prime is 31031211923. The reversal of 31031211817 is 71811213013.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 71811213013 = 19 ⋅3779537527.

It can be written as a sum of positive squares in 2 ways, for example, as 25417606041 + 5613605776 = 159429^2 + 74924^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31031211817 is a prime.

It is a super-2 number, since 2×31031211817² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (31031211517) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 912682684 + ... + 912682717.

It is an arithmetic number, because the mean of its divisors is an integer number (8214144309).

Almost surely, 2^31031211817 is an apocalyptic number.

It is an amenable number.

31031211817 is a deficient number, since it is larger than the sum of its proper divisors (1825365419).

31031211817 is a wasteful number, since it uses less digits than its factorization.

31031211817 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1825365418.

The product of its (nonzero) digits is 1008, while the sum is 28.

The spelling of 31031211817 in words is "thirty-one billion, thirty-one million, two hundred eleven thousand, eight hundred seventeen".