1221086278920 has 64 divisors (see below), whose sum is σ = 3663383137920. Its totient is φ = 325611958784.

The previous prime is 1221086278903. The next prime is 1221086278921. The reversal of 1221086278920 is 298726801221.

It is a self number, because there is not a number n which added to its sum of digits gives 1221086278920.

It is not an unprimeable number, because it can be changed into a prime (1221086278921) 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, 3748069 + ... + 4060811.

It is an arithmetic number, because the mean of its divisors is an integer number (57240361530).

Almost surely, 2^{1221086278920} is an apocalyptic number.

1221086278920 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1221086278920 is an abundant number, since it is smaller than the sum of its proper divisors (2442296859000).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1221086278920 is a wasteful number, since it uses less digits than its factorization.

1221086278920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 345294 (or 345290 counting only the distinct ones).

The product of its (nonzero) digits is 387072, while the sum is 48.

The spelling of 1221086278920 in words is "one trillion, two hundred twenty-one billion, eighty-six million, two hundred seventy-eight thousand, nine hundred twenty".