1899721728 has 88 divisors (see below), whose sum is σ = 5626138560. Its totient is φ = 633231360.

The previous prime is 1899721727. The next prime is 1899721739. The reversal of 1899721728 is 8271279981.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1899721723) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 6708 + ... + 62003.

Almost surely, 2^1899721728 is an apocalyptic number.

1899721728 is a gapful number since it is divisible by the number (18) 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 1899721728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2813069280).

1899721728 is an abundant number, since it is smaller than the sum of its proper divisors (3726416832).

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

1899721728 is an equidigital number, since it uses as much as digits as its factorization.

1899721728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 68740 (or 68716 counting only the distinct ones).

The product of its digits is 1016064, while the sum is 54.

The square root of 1899721728 is about 43585.7973197692. The cubic root of 1899721728 is about 1238.5018604996.

The spelling of 1899721728 in words is "one billion, eight hundred ninety-nine million, seven hundred twenty-one thousand, seven hundred twenty-eight".