1821859 has 4 divisors (see below), whose sum is σ = 1962016. Its totient is φ = 1681704.

The previous prime is 1821857. The next prime is 1821871. The reversal of 1821859 is 9581281.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 9581281 = 29 ⋅330389.

It is a cyclic number.

It is not a de Polignac number, because 1821859 - 2¹ = 1821857 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1821857) 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, 70059 + ... + 70084.

It is an arithmetic number, because the mean of its divisors is an integer number (490504).

2^1821859 is an apocalyptic number.

1821859 is a deficient number, since it is larger than the sum of its proper divisors (140157).

1821859 is a wasteful number, since it uses less digits than its factorization.

1821859 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 140156.

The product of its digits is 5760, while the sum is 34.

The square root of 1821859 is about 1349.7625717140. The cubic root of 1821859 is about 122.1344705598.

The spelling of 1821859 in words is "one million, eight hundred twenty-one thousand, eight hundred fifty-nine".