20086991 has 2 divisors, whose sum is σ = 20086992. Its totient is φ = 20086990.

The previous prime is 20086951. The next prime is 20087021. The reversal of 20086991 is 19968002.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20086991 - 2²² = 15892687 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20086921) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10043495 + 10043496.

It is an arithmetic number, because the mean of its divisors is an integer number (10043496).

Almost surely, 2^20086991 is an apocalyptic number.

20086991 is a deficient number, since it is larger than the sum of its proper divisors (1).

20086991 is an equidigital number, since it uses as much as digits as its factorization.

20086991 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 7776, while the sum is 35.

The square root of 20086991 is about 4481.8512915981. The cubic root of 20086991 is about 271.8347422842.

The spelling of 20086991 in words is "twenty million, eighty-six thousand, nine hundred ninety-one".