1800138720 has 96 divisors (see below), whose sum is σ = 5699520288. Its totient is φ = 477575168.

The previous prime is 1800138719. The next prime is 1800138737. The reversal of 1800138720 is 278310081.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (96).

It is a super-2 number, since 2×1800138720² = 6480998822486476800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a congruent number.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 85042 + ... + 104078.

It is an arithmetic number, because the mean of its divisors is an integer number (59370003).

Almost surely, 2^1800138720 is an apocalyptic number.

1800138720 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1800138720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2849760144).

1800138720 is an abundant number, since it is smaller than the sum of its proper divisors (3899381568).

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

1800138720 is a wasteful number, since it uses less digits than its factorization.

1800138720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19252 (or 19244 counting only the distinct ones).

The product of its (nonzero) digits is 2688, while the sum is 30.

The square root of 1800138720 is about 42428.0416705744. The cubic root of 1800138720 is about 1216.4716473142.

The spelling of 1800138720 in words is "one billion, eight hundred million, one hundred thirty-eight thousand, seven hundred twenty".