1243216123421 has 4 divisors (see below), whose sum is σ = 1264287583200. Its totient is φ = 1222144663644.

The previous prime is 1243216123381. The next prime is 1243216123433.

1243216123421 is nontrivially palindromic in base 10.

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 1243216123421 - 2³⁸ = 968338216477 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 (1243216123921) 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, 10535729801 + ... + 10535729918.

It is an arithmetic number, because the mean of its divisors is an integer number (316071895800).

Almost surely, 2^{1243216123421} is an apocalyptic number.

It is an amenable number.

1243216123421 is a deficient number, since it is larger than the sum of its proper divisors (21071459779).

1243216123421 is an equidigital number, since it uses as much as digits as its factorization.

1243216123421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21071459778.

The product of its digits is 13824, while the sum is 32.

The spelling of 1243216123421 in words is "one trillion, two hundred forty-three billion, two hundred sixteen million, one hundred twenty-three thousand, four hundred twenty-one".