1999643738 has 8 divisors (see below), whose sum is σ = 3001771488. Its totient is φ = 999053244.

The previous prime is 1999643669. The next prime is 1999643741. The reversal of 1999643738 is 8373469991.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a super-2 number, since 2×1999643738² = 7997150157845225288, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 381056 + ... + 386267.

It is an arithmetic number, because the mean of its divisors is an integer number (375221436).

Almost surely, 2^1999643738 is an apocalyptic number.

1999643738 is a deficient number, since it is larger than the sum of its proper divisors (1002127750).

1999643738 is a wasteful number, since it uses less digits than its factorization.

1999643738 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 768628.

The product of its digits is 8817984, while the sum is 59.

The square root of 1999643738 is about 44717.3762423513. The cubic root of 1999643738 is about 1259.8462351202.

The spelling of 1999643738 in words is "one billion, nine hundred ninety-nine million, six hundred forty-three thousand, seven hundred thirty-eight".