1216021 has 2 divisors, whose sum is σ = 1216022. Its totient is φ = 1216020.

The previous prime is 1216013. The next prime is 1216043. The reversal of 1216021 is 1206121.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1134225 + 81796 = 1065^2 + 286^2 .

It is a cyclic number.

It is not a de Polignac number, because 1216021 - 2³ = 1216013 is a prime.

It is a Chen prime.

It is a pancake number, because a pancake can be divided into 1216021 parts by 1559 straight cuts.

It is a junction number, because it is equal to n+sod(n) for n = 1215992 and 1216010.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1216091) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 608010 + 608011.

It is an arithmetic number, because the mean of its divisors is an integer number (608011).

2^1216021 is an apocalyptic number.

It is an amenable number.

1216021 is a deficient number, since it is larger than the sum of its proper divisors (1).

1216021 is an equidigital number, since it uses as much as digits as its factorization.

1216021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 24, while the sum is 13.

The square root of 1216021 is about 1102.7334220019. The cubic root of 1216021 is about 106.7366803799.

The spelling of 1216021 in words is "one million, two hundred sixteen thousand, twenty-one".