1820398 has 4 divisors (see below), whose sum is σ = 2730600. Its totient is φ = 910198.

The previous prime is 1820389. The next prime is 1820407. The reversal of 1820398 is 8930281.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 8930281 = 163 ⋅54787.

It is an interprime number because it is at equal distance from previous prime (1820389) and next prime (1820407).

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 455098 + ... + 455101.

It is an arithmetic number, because the mean of its divisors is an integer number (682650).

2^1820398 is an apocalyptic number.

1820398 is a deficient number, since it is larger than the sum of its proper divisors (910202).

1820398 is an equidigital number, since it uses as much as digits as its factorization.

1820398 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 910201.

The product of its (nonzero) digits is 3456, while the sum is 31.

The square root of 1820398 is about 1349.2212568738. The cubic root of 1820398 is about 122.1018141392.

The spelling of 1820398 in words is "one million, eight hundred twenty thousand, three hundred ninety-eight".