1993639817 has 16 divisors (see below), whose sum is σ = 2167309200. Its totient is φ = 1822943232.

The previous prime is 1993639807. The next prime is 1993639819. The reversal of 1993639817 is 7189363991.

It can be written as a sum of positive squares in 8 ways, for example, as 803665801 + 1189974016 = 28349^2 + 34496^2 .

It is a cyclic number.

It is not a de Polignac number, because 1993639817 - 2¹⁰ = 1993638793 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1993639819) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 837533 + ... + 839909.

It is an arithmetic number, because the mean of its divisors is an integer number (135456825).

Almost surely, 2^1993639817 is an apocalyptic number.

It is an amenable number.

1993639817 is a deficient number, since it is larger than the sum of its proper divisors (173669383).

1993639817 is a wasteful number, since it uses less digits than its factorization.

1993639817 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2972.

The product of its digits is 2204496, while the sum is 56.

The square root of 1993639817 is about 44650.1939189518. The cubic root of 1993639817 is about 1258.5840769191.

The spelling of 1993639817 in words is "one billion, nine hundred ninety-three million, six hundred thirty-nine thousand, eight hundred seventeen".