1221511515441 has 16 divisors (see below), whose sum is σ = 1861716946944. Its totient is φ = 697869305424.

The previous prime is 1221511515391. The next prime is 1221511515457. The reversal of 1221511515441 is 1445151151221.

It is not a de Polignac number, because 1221511515441 - 2¹⁴ = 1221511499057 is a prime.

It is a super-3 number, since 3×1221511515441³ (a number of 37 digits) contains 333 as substring.

It is not an unprimeable number, because it can be changed into a prime (1221511515641) 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 15 ways as a sum of consecutive naturals, for example, 5610415 + ... + 5824068.

It is an arithmetic number, because the mean of its divisors is an integer number (116357309184).

Almost surely, 2^{1221511515441} is an apocalyptic number.

It is an amenable number.

1221511515441 is a deficient number, since it is larger than the sum of its proper divisors (640205431503).

1221511515441 is a wasteful number, since it uses less digits than its factorization.

1221511515441 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11439580.

The product of its digits is 8000, while the sum is 33.

Adding to 1221511515441 its reverse (1445151151221), we get a palindrome (2666662666662).

The spelling of 1221511515441 in words is "one trillion, two hundred twenty-one billion, five hundred eleven million, five hundred fifteen thousand, four hundred forty-one".