20891459 has 2 divisors, whose sum is σ = 20891460. Its totient is φ = 20891458.

The previous prime is 20891447. The next prime is 20891461. The reversal of 20891459 is 95419802.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20891459 - 2⁴ = 20891443 is a prime.

Together with 20891461, 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 (20896459) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10445729 + 10445730.

It is an arithmetic number, because the mean of its divisors is an integer number (10445730).

Almost surely, 2^20891459 is an apocalyptic number.

20891459 is a deficient number, since it is larger than the sum of its proper divisors (1).

20891459 is an equidigital number, since it uses as much as digits as its factorization.

20891459 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 25920, while the sum is 38.

The square root of 20891459 is about 4570.7175585459. The cubic root of 20891459 is about 275.4162687477.

The spelling of 20891459 in words is "twenty million, eight hundred ninety-one thousand, four hundred fifty-nine".