1221542451221 has 8 divisors (see below), whose sum is σ = 1286442736320. Its totient is φ = 1156703023872.

The previous prime is 1221542451187. The next prime is 1221542451229.

1221542451221 is nontrivially palindromic in base 10.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1221542451221 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221542451229) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 15173225 + ... + 15253518.

It is an arithmetic number, because the mean of its divisors is an integer number (160805342040).

Almost surely, 2^{1221542451221} is an apocalyptic number.

It is an amenable number.

1221542451221 is a deficient number, since it is larger than the sum of its proper divisors (64900285099).

1221542451221 is a wasteful number, since it uses less digits than its factorization.

1221542451221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30428875.

The product of its digits is 12800, while the sum is 32.

The spelling of 1221542451221 in words is "one trillion, two hundred twenty-one billion, five hundred forty-two million, four hundred fifty-one thousand, two hundred twenty-one".