1643923 has 4 divisors (see below), whose sum is σ = 1700640. Its totient is φ = 1587208.

The previous prime is 1643893. The next prime is 1643959. The reversal of 1643923 is 3293461.

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 1643923 - 2⁵ = 1643891 is a prime.

It is an Ulam number.

It is a Duffinian number.

1643923 is a lucky number.

It is a junction number, because it is equal to n+sod(n) for n = 1643891 and 1643900.

It is not an unprimeable number, because it can be changed into a prime (1643963) 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, 28315 + ... + 28372.

It is an arithmetic number, because the mean of its divisors is an integer number (425160).

2^1643923 is an apocalyptic number.

1643923 is a deficient number, since it is larger than the sum of its proper divisors (56717).

1643923 is an equidigital number, since it uses as much as digits as its factorization.

1643923 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 56716.

The product of its digits is 3888, while the sum is 28.

The square root of 1643923 is about 1282.1556067810. The cubic root of 1643923 is about 118.0213262230.

The spelling of 1643923 in words is "one million, six hundred forty-three thousand, nine hundred twenty-three".