921819121 has 4 divisors (see below), whose sum is σ = 926188144. Its totient is φ = 917450100.

The previous prime is 921819109. The next prime is 921819137. The reversal of 921819121 is 121918129.

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 921819121 - 2¹⁹ = 921294833 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (921819161) 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, 2184195 + ... + 2184616.

It is an arithmetic number, because the mean of its divisors is an integer number (231547036).

Almost surely, 2^921819121 is an apocalyptic number.

It is an amenable number.

921819121 is a deficient number, since it is larger than the sum of its proper divisors (4369023).

921819121 is a wasteful number, since it uses less digits than its factorization.

921819121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4369022.

The product of its digits is 2592, while the sum is 34.

The square root of 921819121 is about 30361.4742889735. The cubic root of 921819121 is about 973.2294392323.

The spelling of 921819121 in words is "nine hundred twenty-one million, eight hundred nineteen thousand, one hundred twenty-one".