1800555381 has 12 divisors (see below), whose sum is σ = 2626554060. Its totient is φ = 1188484800.

The previous prime is 1800555377. The next prime is 1800555389. The reversal of 1800555381 is 1835550081.

It can be written as a sum of positive squares in 2 ways, for example, as 1050343281 + 750212100 = 32409^2 + 27390^2 .

It is not a de Polignac number, because 1800555381 - 2² = 1800555377 is a prime.

It is a super-2 number, since 2×1800555381² = 6483999360096110322, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1800555389) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 989496 + ... + 991313.

It is an arithmetic number, because the mean of its divisors is an integer number (218879505).

Almost surely, 2^1800555381 is an apocalyptic number.

It is an amenable number.

1800555381 is a deficient number, since it is larger than the sum of its proper divisors (825998679).

1800555381 is a wasteful number, since it uses less digits than its factorization.

1800555381 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1980916 (or 1980913 counting only the distinct ones).

The product of its (nonzero) digits is 24000, while the sum is 36.

The square root of 1800555381 is about 42432.9515942504. The cubic root of 1800555381 is about 1216.5654951173.

The spelling of 1800555381 in words is "one billion, eight hundred million, five hundred fifty-five thousand, three hundred eighty-one".