1221153151421 has 4 divisors (see below), whose sum is σ = 1395603601632. Its totient is φ = 1046702701212.

The previous prime is 1221153151397. The next prime is 1221153151429. The reversal of 1221153151421 is 1241513511221.

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 not a de Polignac number, because 1221153151421 - 2⁶ = 1221153151357 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 (1221153151429) 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, 87225225095 + ... + 87225225108.

It is an arithmetic number, because the mean of its divisors is an integer number (348900900408).

Almost surely, 2^{1221153151421} is an apocalyptic number.

It is an amenable number.

1221153151421 is a deficient number, since it is larger than the sum of its proper divisors (174450450211).

1221153151421 is an equidigital number, since it uses as much as digits as its factorization.

1221153151421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 174450450210.

The product of its digits is 2400, while the sum is 29.

Adding to 1221153151421 its reverse (1241513511221), we get a palindrome (2462666662642).

The spelling of 1221153151421 in words is "one trillion, two hundred twenty-one billion, one hundred fifty-three million, one hundred fifty-one thousand, four hundred twenty-one".