1621806 has 16 divisors (see below), whose sum is σ = 3268944. Its totient is φ = 536384.

The previous prime is 1621793. The next prime is 1621819. The reversal of 1621806 is 6081261.

It is an interprime number because it is at equal distance from previous prime (1621793) and next prime (1621819).

It is a Curzon number.

It is a nialpdrome in base 6.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 165 + ... + 1808.

It is an arithmetic number, because the mean of its divisors is an integer number (204309).

2^1621806 is an apocalyptic number.

1621806 is an abundant number, since it is smaller than the sum of its proper divisors (1647138).

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

1621806 is a wasteful number, since it uses less digits than its factorization.

1621806 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2115.

The product of its (nonzero) digits is 576, while the sum is 24.

The square root of 1621806 is about 1273.5014723195. The cubic root of 1621806 is about 117.4896565514.

The spelling of 1621806 in words is "one million, six hundred twenty-one thousand, eight hundred six".