1820273381 has 4 divisors (see below), whose sum is σ = 1822870764. Its totient is φ = 1817676000.

The previous prime is 1820273339. The next prime is 1820273417. The reversal of 1820273381 is 1833720281.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 1503112900 + 317160481 = 38770^2 + 17809^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1820273381 is a prime.

It is a super-2 number, since 2×1820273381² = 6626790363154342322, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1820273311) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1297640 + ... + 1299041.

It is an arithmetic number, because the mean of its divisors is an integer number (455717691).

Almost surely, 2^1820273381 is an apocalyptic number.

It is an amenable number.

1820273381 is a deficient number, since it is larger than the sum of its proper divisors (2597383).

1820273381 is an equidigital number, since it uses as much as digits as its factorization.

1820273381 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2597382.

The product of its (nonzero) digits is 16128, while the sum is 35.

The square root of 1820273381 is about 42664.6619698317. The cubic root of 1820273381 is about 1220.9902783404.

The spelling of 1820273381 in words is "one billion, eight hundred twenty million, two hundred seventy-three thousand, three hundred eighty-one".