1212221323421 has 4 divisors (see below), whose sum is σ = 1224223514844. Its totient is φ = 1200219132000.

The previous prime is 1212221323409. The next prime is 1212221323433. The reversal of 1212221323421 is 1243231222121.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (1212221323409) and next prime (1212221323433).

It can be written as a sum of positive squares in 2 ways, for example, as 832950100921 + 379271222500 = 912661^2 + 615850^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1212221323421 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 (1212221323121) 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, 6001095560 + ... + 6001095761.

It is an arithmetic number, because the mean of its divisors is an integer number (306055878711).

Almost surely, 2^{1212221323421} is an apocalyptic number.

It is an amenable number.

1212221323421 is a deficient number, since it is larger than the sum of its proper divisors (12002191423).

1212221323421 is a wasteful number, since it uses less digits than its factorization.

1212221323421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12002191422.

The product of its digits is 2304, while the sum is 26.

Adding to 1212221323421 its reverse (1243231222121), we get a palindrome (2455452545542).

The spelling of 1212221323421 in words is "one trillion, two hundred twelve billion, two hundred twenty-one million, three hundred twenty-three thousand, four hundred twenty-one".