999644 has 6 divisors (see below), whose sum is σ = 1749384. Its totient is φ = 499820.

The previous prime is 999631. The next prime is 999653. The reversal of 999644 is 446999.

999644 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a nialpdrome in base 10.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 124952 + ... + 124959.

It is an arithmetic number, because the mean of its divisors is an integer number (291564).

2⁹⁹⁹⁶⁴⁴ is an apocalyptic number.

It is an amenable number.

999644 is a deficient number, since it is larger than the sum of its proper divisors (749740).

999644 is a wasteful number, since it uses less digits than its factorization.

999644 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 249915 (or 249913 counting only the distinct ones).

The product of its digits is 69984, while the sum is 41.

The square root of 999644 is about 999.8219841552. The cubic root of 999644 is about 99.9881319249.

The spelling of 999644 in words is "nine hundred ninety-nine thousand, six hundred forty-four".