1243315421 has 4 divisors (see below), whose sum is σ = 1243487712. Its totient is φ = 1243143132.

The previous prime is 1243315379. The next prime is 1243315429. The reversal of 1243315421 is 1245133421.

It is a happy number.

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 a cyclic number.

It is not a de Polignac number, because 1243315421 - 2³⁰ = 169573597 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 (1243315429) 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, 74825 + ... + 89918.

It is an arithmetic number, because the mean of its divisors is an integer number (310871928).

Almost surely, 2^1243315421 is an apocalyptic number.

It is an amenable number.

1243315421 is a deficient number, since it is larger than the sum of its proper divisors (172291).

1243315421 is an equidigital number, since it uses as much as digits as its factorization.

1243315421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 172290.

The product of its digits is 2880, while the sum is 26.

The square root of 1243315421 is about 35260.6781131617. The cubic root of 1243315421 is about 1075.2937134341.

Adding to 1243315421 its reverse (1245133421), we get a palindrome (2488448842).

The spelling of 1243315421 in words is "one billion, two hundred forty-three million, three hundred fifteen thousand, four hundred twenty-one".