1221512313165 has 64 divisors (see below), whose sum is σ = 1988173071360. Its totient is φ = 640324270080.

The previous prime is 1221512313157. The next prime is 1221512313169. The reversal of 1221512313165 is 5613132151221.

It is not a de Polignac number, because 1221512313165 - 2³ = 1221512313157 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221512313169) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 236221030 + ... + 236226200.

It is an arithmetic number, because the mean of its divisors is an integer number (31065204240).

Almost surely, 2^{1221512313165} is an apocalyptic number.

1221512313165 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1221512313165 is a deficient number, since it is larger than the sum of its proper divisors (766660758195).

1221512313165 is a wasteful number, since it uses less digits than its factorization.

1221512313165 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6362.

The product of its digits is 10800, while the sum is 33.

Adding to 1221512313165 its reverse (5613132151221), we get a palindrome (6834644464386).

The spelling of 1221512313165 in words is "one trillion, two hundred twenty-one billion, five hundred twelve million, three hundred thirteen thousand, one hundred sixty-five".