31997091229 has 4 divisors (see below), whose sum is σ = 33879273084. Its totient is φ = 30114909376.

The previous prime is 31997091211. The next prime is 31997091257. The reversal of 31997091229 is 92219079913.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 92219079913 = 3191 ⋅28899743.

It can be written as a sum of positive squares in 2 ways, for example, as 22333808025 + 9663283204 = 149445^2 + 98302^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31997091229 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31997091289) 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, 941090902 + ... + 941090935.

It is an arithmetic number, because the mean of its divisors is an integer number (8469818271).

Almost surely, 2^31997091229 is an apocalyptic number.

It is an amenable number.

31997091229 is a deficient number, since it is larger than the sum of its proper divisors (1882181855).

31997091229 is a wasteful number, since it uses less digits than its factorization.

31997091229 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1882181854.

The product of its (nonzero) digits is 551124, while the sum is 52.

The spelling of 31997091229 in words is "thirty-one billion, nine hundred ninety-seven million, ninety-one thousand, two hundred twenty-nine".