1616221 has 2 divisors, whose sum is σ = 1616222. Its totient is φ = 1616220.

The previous prime is 1616201. The next prime is 1616227. The reversal of 1616221 is 1226161.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1413721 + 202500 = 1189^2 + 450^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1616221 is a prime.

It is a super-2 number, since 2×1616221² = 5224340641682, which contains 22 as substring.

It is equal to p₁₂₂₂₇₅ and since 1616221 and 122275 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1616227) 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 as a sum of consecutive naturals, namely, 808110 + 808111.

It is an arithmetic number, because the mean of its divisors is an integer number (808111).

2^1616221 is an apocalyptic number.

It is an amenable number.

1616221 is a deficient number, since it is larger than the sum of its proper divisors (1).

1616221 is an equidigital number, since it uses as much as digits as its factorization.

1616221 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 144, while the sum is 19.

The square root of 1616221 is about 1271.3068079736. The cubic root of 1616221 is about 117.3546353871.

The spelling of 1616221 in words is "one million, six hundred sixteen thousand, two hundred twenty-one".