1020891 has 4 divisors (see below), whose sum is σ = 1361192. Its totient is φ = 680592.

The previous prime is 1020881. The next prime is 1020893. The reversal of 1020891 is 1980201.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1980201 = 3 ⋅660067.

It is not a de Polignac number, because 1020891 - 2⁶ = 1020827 is a prime.

It is an Ulam number.

It is a D-number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1020893) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 170146 + ... + 170151.

It is an arithmetic number, because the mean of its divisors is an integer number (340298).

2^1020891 is an apocalyptic number.

1020891 is a deficient number, since it is larger than the sum of its proper divisors (340301).

1020891 is an equidigital number, since it uses as much as digits as its factorization.

1020891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 340300.

The product of its (nonzero) digits is 144, while the sum is 21.

The square root of 1020891 is about 1010.3915082779. The cubic root of 1020891 is about 100.6915729104.

The spelling of 1020891 in words is "one million, twenty thousand, eight hundred ninety-one".