1721666 has 8 divisors (see below), whose sum is σ = 2718480. Its totient is φ = 815508.

The previous prime is 1721659. The next prime is 1721683. The reversal of 1721666 is 6661271.

It is a sphenic number, since it is the product of 3 distinct primes.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 22616 + ... + 22691.

It is an arithmetic number, because the mean of its divisors is an integer number (339810).

2^1721666 is an apocalyptic number.

1721666 is a deficient number, since it is larger than the sum of its proper divisors (996814).

1721666 is a wasteful number, since it uses less digits than its factorization.

1721666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 45328.

The product of its digits is 3024, while the sum is 29.

The square root of 1721666 is about 1312.1227076764. The cubic root of 1721666 is about 119.8532001178.

The spelling of 1721666 in words is "one million, seven hundred twenty-one thousand, six hundred sixty-six".