20117731 has 2 divisors, whose sum is σ = 20117732. Its totient is φ = 20117730.

The previous prime is 20117723. The next prime is 20117737. The reversal of 20117731 is 13771102.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20117731 - 2³ = 20117723 is a prime.

It is a super-2 number, since 2×20117731² = 809446201176722, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (20117737) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10058865 + 10058866.

It is an arithmetic number, because the mean of its divisors is an integer number (10058866).

Almost surely, 2^20117731 is an apocalyptic number.

20117731 is a deficient number, since it is larger than the sum of its proper divisors (1).

20117731 is an equidigital number, since it uses as much as digits as its factorization.

20117731 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 294, while the sum is 22.

The square root of 20117731 is about 4485.2793669960. The cubic root of 20117731 is about 271.9733384695.

Adding to 20117731 its reverse (13771102), we get a palindrome (33888833).

The spelling of 20117731 in words is "twenty million, one hundred seventeen thousand, seven hundred thirty-one".