1221434123421 has 64 divisors (see below), whose sum is σ = 1772271083520. Its totient is φ = 746621890560.

The previous prime is 1221434123407. The next prime is 1221434123471. The reversal of 1221434123421 is 1243214341221.

It is a happy number.

It is not a de Polignac number, because 1221434123421 - 2¹¹ = 1221434121373 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221434123471) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 23984041 + ... + 24034913.

It is an arithmetic number, because the mean of its divisors is an integer number (27691735680).

Almost surely, 2^{1221434123421} is an apocalyptic number.

It is an amenable number.

1221434123421 is a deficient number, since it is larger than the sum of its proper divisors (550836960099).

1221434123421 is a wasteful number, since it uses less digits than its factorization.

1221434123421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 51126.

The product of its digits is 9216, while the sum is 30.

Adding to 1221434123421 its reverse (1243214341221), we get a palindrome (2464648464642).

The spelling of 1221434123421 in words is "one trillion, two hundred twenty-one billion, four hundred thirty-four million, one hundred twenty-three thousand, four hundred twenty-one".