9138921 has 16 divisors (see below), whose sum is σ = 13382400. Its totient is φ = 5501520.

The previous prime is 9138917. The next prime is 9138929. The reversal of 9138921 is 1298319.

It is not a de Polignac number, because 9138921 - 2² = 9138917 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is a Curzon number.

9138921 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (9138929) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4530 + ... + 6228.

It is an arithmetic number, because the mean of its divisors is an integer number (836400).

Almost surely, 2^9138921 is an apocalyptic number.

It is an amenable number.

9138921 is a deficient number, since it is larger than the sum of its proper divisors (4243479).

9138921 is a wasteful number, since it uses less digits than its factorization.

9138921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1876.

The product of its digits is 3888, while the sum is 33.

The square root of 9138921 is about 3023.0648355601. The cubic root of 9138921 is about 209.0731717267.

The spelling of 9138921 in words is "nine million, one hundred thirty-eight thousand, nine hundred twenty-one".