20591971 has 2 divisors, whose sum is σ = 20591972. Its totient is φ = 20591970.

The previous prime is 20591939. The next prime is 20591983. The reversal of 20591971 is 17919502.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20591971 - 2⁵ = 20591939 is a prime.

It is not a weakly prime, because it can be changed into another prime (20591911) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10295985 + 10295986.

It is an arithmetic number, because the mean of its divisors is an integer number (10295986).

Almost surely, 2^20591971 is an apocalyptic number.

20591971 is a deficient number, since it is larger than the sum of its proper divisors (1).

20591971 is an equidigital number, since it uses as much as digits as its factorization.

20591971 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5670, while the sum is 34.

The square root of 20591971 is about 4537.8377009320. The cubic root of 20591971 is about 274.0938593678.

The spelling of 20591971 in words is "twenty million, five hundred ninety-one thousand, nine hundred seventy-one".