2181923 has 4 divisors (see below), whose sum is σ = 2189208. Its totient is φ = 2174640.

The previous prime is 2181919. The next prime is 2181937. The reversal of 2181923 is 3291812.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 2181923 - 2² = 2181919 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 2181892 and 2181901.

It is not an unprimeable number, because it can be changed into a prime (2181953) 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, 3173 + ... + 3798.

It is an arithmetic number, because the mean of its divisors is an integer number (547302).

2^2181923 is an apocalyptic number.

2181923 is a deficient number, since it is larger than the sum of its proper divisors (7285).

2181923 is an equidigital number, since it uses as much as digits as its factorization.

2181923 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7284.

The product of its digits is 864, while the sum is 26.

The square root of 2181923 is about 1477.1333724481. The cubic root of 2181923 is about 129.7019404155.

The spelling of 2181923 in words is "two million, one hundred eighty-one thousand, nine hundred twenty-three".