20646091 has 2 divisors, whose sum is σ = 20646092. Its totient is φ = 20646090.

The previous prime is 20646089. The next prime is 20646107. The reversal of 20646091 is 19064602.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20646091 - 2¹ = 20646089 is a prime.

It is a super-2 number, since 2×20646091² = 852522147160562, which contains 22 as substring.

Together with 20646089, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (20646011) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10323045 + 10323046.

It is an arithmetic number, because the mean of its divisors is an integer number (10323046).

Almost surely, 2^20646091 is an apocalyptic number.

20646091 is a deficient number, since it is larger than the sum of its proper divisors (1).

20646091 is an equidigital number, since it uses as much as digits as its factorization.

20646091 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2592, while the sum is 28.

The square root of 20646091 is about 4543.7969804999. The cubic root of 20646091 is about 274.3337746084. Note that the first 3 decimals are identical.

The spelling of 20646091 in words is "twenty million, six hundred forty-six thousand, ninety-one".