20898091 has 2 divisors, whose sum is σ = 20898092. Its totient is φ = 20898090.

The previous prime is 20898047. The next prime is 20898109. The reversal of 20898091 is 19089802.

Together with next prime (20898109) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20898091 - 2⁹ = 20897579 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20898091.

It is not a weakly prime, because it can be changed into another prime (20898041) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10449045 + 10449046.

It is an arithmetic number, because the mean of its divisors is an integer number (10449046).

Almost surely, 2^20898091 is an apocalyptic number.

20898091 is a deficient number, since it is larger than the sum of its proper divisors (1).

20898091 is an equidigital number, since it uses as much as digits as its factorization.

20898091 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 10368, while the sum is 37.

The square root of 20898091 is about 4571.4429888166. The cubic root of 20898091 is about 275.4454093238.

The spelling of 20898091 in words is "twenty million, eight hundred ninety-eight thousand, ninety-one".