1938921 has 4 divisors (see below), whose sum is σ = 2585232. Its totient is φ = 1292612.

The previous prime is 1938907. The next prime is 1938949. The reversal of 1938921 is 1298391.

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, and also an emirpimes, since its reverse is a distinct semiprime: 1298391 = 3 ⋅432797.

It is a cyclic number.

It is not a de Polignac number, because 1938921 - 2⁵ = 1938889 is a prime.

It is a D-number.

1938921 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (1938971) 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 3 ways as a sum of consecutive naturals, for example, 323151 + ... + 323156.

It is an arithmetic number, because the mean of its divisors is an integer number (646308).

2^1938921 is an apocalyptic number.

It is an amenable number.

1938921 is a deficient number, since it is larger than the sum of its proper divisors (646311).

1938921 is an equidigital number, since it uses as much as digits as its factorization.

1938921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 646310.

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

The square root of 1938921 is about 1392.4514354188. The cubic root of 1938921 is about 124.6962437886.

The spelling of 1938921 in words is "one million, nine hundred thirty-eight thousand, nine hundred twenty-one".