31166728091 has 4 divisors (see below), whose sum is σ = 31167840792. Its totient is φ = 31165615392.

The previous prime is 31166728081. The next prime is 31166728129. The reversal of 31166728091 is 19082766113.

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-31166728091 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (31166728081) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 513221 + ... + 570726.

It is an arithmetic number, because the mean of its divisors is an integer number (7791960198).

Almost surely, 2^31166728091 is an apocalyptic number.

31166728091 is a deficient number, since it is larger than the sum of its proper divisors (1112701).

31166728091 is a wasteful number, since it uses less digits than its factorization.

31166728091 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1112700.

The product of its (nonzero) digits is 108864, while the sum is 44.

The spelling of 31166728091 in words is "thirty-one billion, one hundred sixty-six million, seven hundred twenty-eight thousand, ninety-one".