999809866 has 32 divisors (see below), whose sum is σ = 1664929728. Its totient is φ = 446499840.

The previous prime is 999809827. The next prime is 999809879. The reversal of 999809866 is 668908999.

It is a junction number, because it is equal to n+sod(n) for n = 999809798 and 999809807.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 351000 + ... + 353836.

It is an arithmetic number, because the mean of its divisors is an integer number (52029054).

Almost surely, 2^999809866 is an apocalyptic number.

999809866 is a deficient number, since it is larger than the sum of its proper divisors (665119862).

999809866 is a wasteful number, since it uses less digits than its factorization.

999809866 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3126.

The product of its (nonzero) digits is 15116544, while the sum is 64.

The square root of 999809866 is about 31619.7701762679. The cubic root of 999809866 is about 999.9366179828.

The spelling of 999809866 in words is "nine hundred ninety-nine million, eight hundred nine thousand, eight hundred sixty-six".