999000821 has 16 divisors (see below), whose sum is σ = 1234934400. Its totient is φ = 786950208.

The previous prime is 999000817. The next prime is 999000841. The reversal of 999000821 is 128000999.

It is a cyclic number.

It is not a de Polignac number, because 999000821 - 2² = 999000817 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (999000841) 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, 3131 + ... + 44808.

It is an arithmetic number, because the mean of its divisors is an integer number (77183400).

Almost surely, 2^999000821 is an apocalyptic number.

999000821 is a gapful number since it is divisible by the number (91) formed by its first and last digit.

It is an amenable number.

999000821 is a deficient number, since it is larger than the sum of its proper divisors (235933579).

999000821 is a wasteful number, since it uses less digits than its factorization.

999000821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 48188.

The product of its (nonzero) digits is 11664, while the sum is 38.

The square root of 999000821 is about 31606.9742462008. The cubic root of 999000821 is about 999.6668293430. Note that the first 3 decimals are identical.

The spelling of 999000821 in words is "nine hundred ninety-nine million, eight hundred twenty-one", and thus it is an aban number.