20117931 has 4 divisors (see below), whose sum is σ = 26823912. Its totient is φ = 13411952.

The previous prime is 20117917. The next prime is 20117947. The reversal of 20117931 is 13971102.

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

It is a cyclic number.

It is not a de Polignac number, because 20117931 - 2¹⁰ = 20116907 is a prime.

It is a super-2 number, since 2×20117931² = 809462295441522, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (20117971) 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, 3352986 + ... + 3352991.

It is an arithmetic number, because the mean of its divisors is an integer number (6705978).

Almost surely, 2^20117931 is an apocalyptic number.

20117931 is a deficient number, since it is larger than the sum of its proper divisors (6705981).

20117931 is an equidigital number, since it uses as much as digits as its factorization.

20117931 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6705980.

The product of its (nonzero) digits is 378, while the sum is 24.

The square root of 20117931 is about 4485.3016620959. The cubic root of 20117931 is about 271.9742397389.

The spelling of 20117931 in words is "twenty million, one hundred seventeen thousand, nine hundred thirty-one".