16820891 has 2 divisors, whose sum is σ = 16820892. Its totient is φ = 16820890.

The previous prime is 16820861. The next prime is 16820893. The reversal of 16820891 is 19802861.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 16820891 - 2¹⁴ = 16804507 is a prime.

Together with 16820893, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (16820893) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8410445 + 8410446.

It is an arithmetic number, because the mean of its divisors is an integer number (8410446).

Almost surely, 2^16820891 is an apocalyptic number.

16820891 is a deficient number, since it is larger than the sum of its proper divisors (1).

16820891 is an equidigital number, since it uses as much as digits as its factorization.

16820891 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 6912, while the sum is 35.

The square root of 16820891 is about 4101.3279556748. The cubic root of 16820891 is about 256.2219500528.

The spelling of 16820891 in words is "sixteen million, eight hundred twenty thousand, eight hundred ninety-one".