1721864 has 32 divisors (see below), whose sum is σ = 3421440. Its totient is φ = 811200.

The previous prime is 1721857. The next prime is 1721887. The reversal of 1721864 is 4681271.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 13079 + ... + 13209.

It is an arithmetic number, because the mean of its divisors is an integer number (106920).

2^1721864 is an apocalyptic number.

It is an amenable number.

1721864 is a deficient number, since it is larger than the sum of its proper divisors (1699576).

1721864 is a wasteful number, since it uses less digits than its factorization.

1721864 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 221 (or 217 counting only the distinct ones).

The product of its digits is 2688, while the sum is 29.

The square root of 1721864 is about 1312.1981557676. The cubic root of 1721864 is about 119.8577945095.

The spelling of 1721864 in words is "one million, seven hundred twenty-one thousand, eight hundred sixty-four".