1221511515226 has 16 divisors (see below), whose sum is σ = 1881311660928. Its totient is φ = 594476754400.

The previous prime is 1221511515209. The next prime is 1221511515233. The reversal of 1221511515226 is 6225151151221.

It is a junction number, because it is equal to n+sod(n) for n = 1221511515191 and 1221511515200.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 17245960 + ... + 17316643.

It is an arithmetic number, because the mean of its divisors is an integer number (117581978808).

Almost surely, 2^{1221511515226} is an apocalyptic number.

1221511515226 is a deficient number, since it is larger than the sum of its proper divisors (659800145702).

1221511515226 is a wasteful number, since it uses less digits than its factorization.

1221511515226 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 34563077.

The product of its digits is 12000, while the sum is 34.

Adding to 1221511515226 its reverse (6225151151221), we get a palindrome (7446662666447).

The spelling of 1221511515226 in words is "one trillion, two hundred twenty-one billion, five hundred eleven million, five hundred fifteen thousand, two hundred twenty-six".