20201891 has 2 divisors, whose sum is σ = 20201892. Its totient is φ = 20201890.

The previous prime is 20201849. The next prime is 20201897. The reversal of 20201891 is 19810202.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20201891 - 2⁶ = 20201827 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (20201897) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10100945 + 10100946.

It is an arithmetic number, because the mean of its divisors is an integer number (10100946).

Almost surely, 2^20201891 is an apocalyptic number.

20201891 is a deficient number, since it is larger than the sum of its proper divisors (1).

20201891 is an equidigital number, since it uses as much as digits as its factorization.

20201891 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 288, while the sum is 23.

The square root of 20201891 is about 4494.6513769146. The cubic root of 20201891 is about 272.3520662694.

The spelling of 20201891 in words is "twenty million, two hundred one thousand, eight hundred ninety-one".