999981693 has 36 divisors (see below), whose sum is σ = 1510278588. Its totient is φ = 662048640.

The previous prime is 999981659. The next prime is 999981713. The reversal of 999981693 is 396189999.

It can be written as a sum of positive squares in 2 ways, for example, as 563255289 + 436726404 = 23733^2 + 20898^2 .

It is not a de Polignac number, because 999981693 - 2²² = 995787389 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 999981693.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (999981613) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 1134613 + ... + 1135493.

It is an arithmetic number, because the mean of its divisors is an integer number (41952183).

Almost surely, 2^999981693 is an apocalyptic number.

It is an amenable number.

999981693 is a deficient number, since it is larger than the sum of its proper divisors (510296895).

999981693 is an frugal number, since it uses more digits than its factorization.

999981693 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1078 (or 1057 counting only the distinct ones).

The product of its digits is 8503056, while the sum is 63.

The square root of 999981693 is about 31622.4871412734. The cubic root of 999981693 is about 999.9938976294.

The spelling of 999981693 in words is "nine hundred ninety-nine million, nine hundred eighty-one thousand, six hundred ninety-three".