1218421 has 2 divisors, whose sum is σ = 1218422. Its totient is φ = 1218420.

The previous prime is 1218401. The next prime is 1218433. The reversal of 1218421 is 1248121.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 617796 + 600625 = 786^2 + 775^2 .

It is a cyclic number.

It is not a de Polignac number, because 1218421 - 2¹¹ = 1216373 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1218401) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 609210 + 609211.

It is an arithmetic number, because the mean of its divisors is an integer number (609211).

2^1218421 is an apocalyptic number.

It is an amenable number.

1218421 is a deficient number, since it is larger than the sum of its proper divisors (1).

1218421 is an equidigital number, since it uses as much as digits as its factorization.

1218421 is an evil number, because the sum of its binary digits is even.

The product of its digits is 128, while the sum is 19.

The square root of 1218421 is about 1103.8210905758. The cubic root of 1218421 is about 106.8068545213.

The spelling of 1218421 in words is "one million, two hundred eighteen thousand, four hundred twenty-one".