921001091 has 4 divisors (see below), whose sum is σ = 921063000. Its totient is φ = 920939184.

The previous prime is 921001063. The next prime is 921001097. The reversal of 921001091 is 190100129.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-921001091 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (921001097) 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, 6335 + ... + 43383.

It is an arithmetic number, because the mean of its divisors is an integer number (230265750).

Almost surely, 2^921001091 is an apocalyptic number.

921001091 is a deficient number, since it is larger than the sum of its proper divisors (61909).

921001091 is a wasteful number, since it uses less digits than its factorization.

921001091 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 61908.

The product of its (nonzero) digits is 162, while the sum is 23.

The square root of 921001091 is about 30347.9997858178. Note that the first 3 decimals coincide. The cubic root of 921001091 is about 972.9414700512.

The spelling of 921001091 in words is "nine hundred twenty-one million, one thousand, ninety-one".