1820390 has 64 divisors (see below), whose sum is σ = 4112640. Its totient is φ = 570240.

The previous prime is 1820389. The next prime is 1820407. The reversal of 1820390 is 930281.

1820390 = 161² + 162² + ... + 212².

It is a super-3 number, since 3×1820390³ = 18097333015575957000, which contains 333 as substring.

It is a Curzon number.

It is a plaindrome in base 14.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 27137 + ... + 27203.

It is an arithmetic number, because the mean of its divisors is an integer number (64260).

2^1820390 is an apocalyptic number.

1820390 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

1820390 is an abundant number, since it is smaller than the sum of its proper divisors (2292250).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1820390 is a wasteful number, since it uses less digits than its factorization.

1820390 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 117.

The product of its (nonzero) digits is 432, while the sum is 23.

The square root of 1820390 is about 1349.2182921974. The cubic root of 1820390 is about 122.1016352743.

The spelling of 1820390 in words is "one million, eight hundred twenty thousand, three hundred ninety".