921638093 has 4 divisors (see below), whose sum is σ = 921712860. Its totient is φ = 921563328.

The previous prime is 921638089. The next prime is 921638099. The reversal of 921638093 is 390836129.

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, and also an emirpimes, since its reverse is a distinct semiprime: 390836129 = 10607 ⋅36847.

It can be written as a sum of positive squares in 2 ways, for example, as 349615204 + 572022889 = 18698^2 + 23917^2 .

It is a cyclic number.

It is not a de Polignac number, because 921638093 - 2² = 921638089 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 921638093.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (921638099) 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, 14030 + ... + 45167.

It is an arithmetic number, because the mean of its divisors is an integer number (230428215).

Almost surely, 2^921638093 is an apocalyptic number.

It is an amenable number.

921638093 is a deficient number, since it is larger than the sum of its proper divisors (74767).

921638093 is a wasteful number, since it uses less digits than its factorization.

921638093 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 74766.

The product of its (nonzero) digits is 69984, while the sum is 41.

The square root of 921638093 is about 30358.4929303152. The cubic root of 921638093 is about 973.1657270538.

The spelling of 921638093 in words is "nine hundred twenty-one million, six hundred thirty-eight thousand, ninety-three".