1999864 has 32 divisors (see below), whose sum is σ = 4032000. Its totient is φ = 927072.

The previous prime is 1999859. The next prime is 1999867. The reversal of 1999864 is 4689991.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1999867) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8857 + ... + 9079.

It is an arithmetic number, because the mean of its divisors is an integer number (126000).

2^1999864 is an apocalyptic number.

It is an amenable number.

1999864 is an abundant number, since it is smaller than the sum of its proper divisors (2032136).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1999864 is a wasteful number, since it uses less digits than its factorization.

1999864 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 307 (or 303 counting only the distinct ones).

The product of its digits is 139968, while the sum is 46.

The square root of 1999864 is about 1414.1654782945. The cubic root of 1999864 is about 125.9892491037.

The spelling of 1999864 in words is "one million, nine hundred ninety-nine thousand, eight hundred sixty-four".