1821999 has 8 divisors (see below), whose sum is σ = 2488752. Its totient is φ = 1184960.

The previous prime is 1821997. The next prime is 1822003. The reversal of 1821999 is 9991281.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1821999 - 2¹ = 1821997 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1821997) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7284 + ... + 7529.

It is an arithmetic number, because the mean of its divisors is an integer number (311094).

2^1821999 is an apocalyptic number.

1821999 is a deficient number, since it is larger than the sum of its proper divisors (666753).

1821999 is a wasteful number, since it uses less digits than its factorization.

1821999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14857.

The product of its digits is 11664, while the sum is 39.

The square root of 1821999 is about 1349.8144316905. The cubic root of 1821999 is about 122.1375989372.

The spelling of 1821999 in words is "one million, eight hundred twenty-one thousand, nine hundred ninety-nine".