999613821 has 16 divisors (see below), whose sum is σ = 1424174400. Its totient is φ = 621451008.

The previous prime is 999613801. The next prime is 999613829. The reversal of 999613821 is 128316999.

It is not a de Polignac number, because 999613821 - 2¹⁰ = 999612797 is a prime.

It is a super-2 number, since 2×999613821² = 1998455582268440082, which contains 22 as substring.

999613821 is a modest number, since divided by 13821 gives 9996 as remainder.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (999613829) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 84351 + ... + 95468.

It is an arithmetic number, because the mean of its divisors is an integer number (89010900).

Almost surely, 2^999613821 is an apocalyptic number.

It is an amenable number.

999613821 is a deficient number, since it is larger than the sum of its proper divisors (424560579).

999613821 is a wasteful number, since it uses less digits than its factorization.

999613821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 179948.

The product of its digits is 209952, while the sum is 48.

The square root of 999613821 is about 31616.6699859425. The cubic root of 999613821 is about 999.8712570926.

The spelling of 999613821 in words is "nine hundred ninety-nine million, six hundred thirteen thousand, eight hundred twenty-one".