1421521221 has 4 divisors (see below), whose sum is σ = 1895361632. Its totient is φ = 947680812.

The previous prime is 1421521193. The next prime is 1421521223. The reversal of 1421521221 is 1221251241.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 1421521221 - 2¹⁰ = 1421520197 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1421521223) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 236920201 + ... + 236920206.

It is an arithmetic number, because the mean of its divisors is an integer number (473840408).

Almost surely, 2^1421521221 is an apocalyptic number.

It is an amenable number.

1421521221 is a deficient number, since it is larger than the sum of its proper divisors (473840411).

1421521221 is an equidigital number, since it uses as much as digits as its factorization.

1421521221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 473840410.

The product of its digits is 320, while the sum is 21.

The square root of 1421521221 is about 37703.0664668008. The cubic root of 1421521221 is about 1124.3920919140.

Adding to 1421521221 its reverse (1221251241), we get a palindrome (2642772462).

The spelling of 1421521221 in words is "one billion, four hundred twenty-one million, five hundred twenty-one thousand, two hundred twenty-one".