31091378099 has 4 divisors (see below), whose sum is σ = 32727766440. Its totient is φ = 29454989760.

The previous prime is 31091378093. The next prime is 31091378117. The reversal of 31091378099 is 99087319013.

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: 99087319013 = 37 ⋅2678035649.

It is a cyclic number.

It is not a de Polignac number, because 31091378099 - 2¹² = 31091374003 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (31091378093) 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, 818194142 + ... + 818194179.

It is an arithmetic number, because the mean of its divisors is an integer number (8181941610).

Almost surely, 2^31091378099 is an apocalyptic number.

31091378099 is a deficient number, since it is larger than the sum of its proper divisors (1636388341).

31091378099 is a wasteful number, since it uses less digits than its factorization.

31091378099 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1636388340.

The product of its (nonzero) digits is 367416, while the sum is 50.

The spelling of 31091378099 in words is "thirty-one billion, ninety-one million, three hundred seventy-eight thousand, ninety-nine".