891020121 has 4 divisors (see below), whose sum is σ = 1188026832. Its totient is φ = 594013412.

The previous prime is 891020093. The next prime is 891020129. The reversal of 891020121 is 121020198.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 891020121 - 2⁶ = 891020057 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 891020091 and 891020100.

It is not an unprimeable number, because it can be changed into a prime (891020129) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 148503351 + ... + 148503356.

It is an arithmetic number, because the mean of its divisors is an integer number (297006708).

Almost surely, 2^891020121 is an apocalyptic number.

It is an amenable number.

891020121 is a deficient number, since it is larger than the sum of its proper divisors (297006711).

891020121 is a wasteful number, since it uses less digits than its factorization.

891020121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 297006710.

The product of its (nonzero) digits is 288, while the sum is 24.

The square root of 891020121 is about 29849.9601507272. The cubic root of 891020121 is about 962.2675423559.

The spelling of 891020121 in words is "eight hundred ninety-one million, twenty thousand, one hundred twenty-one".