20648891 has 2 divisors, whose sum is σ = 20648892. Its totient is φ = 20648890.

The previous prime is 20648861. The next prime is 20648893. The reversal of 20648891 is 19884602.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20648891 - 2⁶ = 20648827 is a prime.

Together with 20648893, 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 (20648893) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10324445 + 10324446.

It is an arithmetic number, because the mean of its divisors is an integer number (10324446).

Almost surely, 2^20648891 is an apocalyptic number.

20648891 is a deficient number, since it is larger than the sum of its proper divisors (1).

20648891 is an equidigital number, since it uses as much as digits as its factorization.

20648891 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 27648, while the sum is 38.

The square root of 20648891 is about 4544.1050824117. The cubic root of 20648891 is about 274.3461756621.

The spelling of 20648891 in words is "twenty million, six hundred forty-eight thousand, eight hundred ninety-one".