1999019893689 has 81 divisors (see below), whose sum is σ = 3637851649263. Its totient is φ = 1054224478944.

The previous prime is 1999019893679. The next prime is 1999019893733. The reversal of 1999019893689 is 9863989109991.

The square root of 1999019893689 is 1413867.

It is a perfect power (a square), and thus also a powerful number.

1999019893689 is a `hidden beast` number, since 1 + 99 + 90 + 1 + 9 + 89 + 368 + 9 = 666.

It can be written as a sum of positive squares in only one way, i.e., 295713002025 + 1703306891664 = 543795^2 + 1305108^2 .

It is not a de Polignac number, because 1999019893689 - 2⁵ = 1999019893657 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1999019893639) by changing a digit.

It is a polite number, since it can be written in 80 ways as a sum of consecutive naturals, for example, 385983102 + ... + 385988280.

Almost surely, 2^{1999019893689} is an apocalyptic number.

1999019893689 is the 1413867-th square number.

1999019893689 is the 706934-th centered octagonal number.

It is an amenable number.

1999019893689 is a deficient number, since it is larger than the sum of its proper divisors (1638831755574).

1999019893689 is an frugal number, since it uses more digits than its factorization.

1999019893689 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10404 (or 5202 counting only the distinct ones).

The product of its (nonzero) digits is 612220032, while the sum is 81.

Multiplying 1999019893689 by its sum of digits (81), we get a square (161920611388809 = 12724803²).

The spelling of 1999019893689 in words is "one trillion, nine hundred ninety-nine billion, nineteen million, eight hundred ninety-three thousand, six hundred eighty-nine".