1221421 has 2 divisors, whose sum is σ = 1221422. Its totient is φ = 1221420.

The previous prime is 1221391. The next prime is 1221427. The reversal of 1221421 is 1241221.

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., 1179396 + 42025 = 1086^2 + 205^2 .

It is a cyclic number.

It is not a de Polignac number, because 1221421 - 2¹⁵ = 1188653 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1221427) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610710 + 610711.

It is an arithmetic number, because the mean of its divisors is an integer number (610711).

2^1221421 is an apocalyptic number.

It is an amenable number.

1221421 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221421 is an equidigital number, since it uses as much as digits as its factorization.

1221421 is an evil number, because the sum of its binary digits is even.

The product of its digits is 32, while the sum is 13.

The square root of 1221421 is about 1105.1791709945. The cubic root of 1221421 is about 106.8944427311.

Adding to 1221421 its reverse (1241221), we get a palindrome (2462642).

The spelling of 1221421 in words is "one million, two hundred twenty-one thousand, four hundred twenty-one".