20812091 has 2 divisors, whose sum is σ = 20812092. Its totient is φ = 20812090.

The previous prime is 20812039. The next prime is 20812123. The reversal of 20812091 is 19021802.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20812091 - 2¹⁴ = 20795707 is a prime.

It is not a weakly prime, because it can be changed into another prime (20812021) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10406045 + 10406046.

It is an arithmetic number, because the mean of its divisors is an integer number (10406046).

Almost surely, 2^20812091 is an apocalyptic number.

20812091 is a deficient number, since it is larger than the sum of its proper divisors (1).

20812091 is an equidigital number, since it uses as much as digits as its factorization.

20812091 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 288, while the sum is 23.

The square root of 20812091 is about 4562.0270713796. The cubic root of 20812091 is about 275.0670514186.

Adding to 20812091 its reverse (19021802), we get a palindrome (39833893).

The spelling of 20812091 in words is "twenty million, eight hundred twelve thousand, ninety-one".