1606921 has 2 divisors, whose sum is σ = 1606922. Its totient is φ = 1606920.

The previous prime is 1606909. The next prime is 1606951. The reversal of 1606921 is 1296061.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1587600 + 19321 = 1260^2 + 139^2 .

It is a cyclic number.

It is not a de Polignac number, because 1606921 - 2⁵ = 1606889 is a prime.

It is not a weakly prime, because it can be changed into another prime (1606901) by changing a digit.

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 as a sum of consecutive naturals, namely, 803460 + 803461.

It is an arithmetic number, because the mean of its divisors is an integer number (803461).

2^1606921 is an apocalyptic number.

It is an amenable number.

1606921 is a deficient number, since it is larger than the sum of its proper divisors (1).

1606921 is an equidigital number, since it uses as much as digits as its factorization.

1606921 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 648, while the sum is 25.

The square root of 1606921 is about 1267.6438774356. The cubic root of 1606921 is about 117.1291096725.

The spelling of 1606921 in words is "one million, six hundred six thousand, nine hundred twenty-one".