1621666 has 8 divisors (see below), whose sum is σ = 2439360. Its totient is φ = 808548.

The previous prime is 1621657. The next prime is 1621667. The reversal of 1621666 is 6661261.

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

It is not an unprimeable number, because it can be changed into a prime (1621667) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 46 + ... + 1801.

It is an arithmetic number, because the mean of its divisors is an integer number (304920).

2^1621666 is an apocalyptic number.

1621666 is a deficient number, since it is larger than the sum of its proper divisors (817694).

1621666 is a wasteful number, since it uses less digits than its factorization.

1621666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2288.

The product of its digits is 2592, while the sum is 28.

The square root of 1621666 is about 1273.4465045694. The cubic root of 1621666 is about 117.4862757473.

The spelling of 1621666 in words is "one million, six hundred twenty-one thousand, six hundred sixty-six".