1820819 has 32 divisors (see below), whose sum is σ = 2612736. Its totient is φ = 1221120.

The previous prime is 1820813. The next prime is 1820821. The reversal of 1820819 is 9180281.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1820819 is a prime.

It is a super-2 number, since 2×1820819² = 6630763661522, which contains 22 as substring.

It is a Smith number, since the sum of its digits (29) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

1820819 is a modest number, since divided by 819 gives 182 as remainder.

It is a junction number, because it is equal to n+sod(n) for n = 1820791 and 1820800.

It is not an unprimeable number, because it can be changed into a prime (1820813) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 16964 + ... + 17070.

It is an arithmetic number, because the mean of its divisors is an integer number (81648).

2^1820819 is an apocalyptic number.

1820819 is a deficient number, since it is larger than the sum of its proper divisors (791917).

1820819 is a wasteful number, since it uses less digits than its factorization.

1820819 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 155.

The product of its (nonzero) digits is 1152, while the sum is 29.

The square root of 1820819 is about 1349.3772637776. The cubic root of 1820819 is about 122.1112261655. Note that the first 3 decimals are identical.

The spelling of 1820819 in words is "one million, eight hundred twenty thousand, eight hundred nineteen".