1216421 has 2 divisors, whose sum is σ = 1216422. Its totient is φ = 1216420.

The previous prime is 1216417. The next prime is 1216433. The reversal of 1216421 is 1246121.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1079521 + 136900 = 1039^2 + 370^2 .

It is a cyclic number.

It is not a de Polignac number, because 1216421 - 2² = 1216417 is a prime.

It is a super-3 number, since 3×1216421³ = 5399741655533359383, which contains 333 as substring.

It is a plaindrome in base 13.

It is a self number, because there is not a number n which added to its sum of digits gives 1216421.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1216441) 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, 608210 + 608211.

It is an arithmetic number, because the mean of its divisors is an integer number (608211).

2^1216421 is an apocalyptic number.

It is an amenable number.

1216421 is a deficient number, since it is larger than the sum of its proper divisors (1).

1216421 is an equidigital number, since it uses as much as digits as its factorization.

1216421 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 96, while the sum is 17.

The square root of 1216421 is about 1102.9147745860. The cubic root of 1216421 is about 106.7483824782.

The spelling of 1216421 in words is "one million, two hundred sixteen thousand, four hundred twenty-one".