1221805783416 has 64 divisors (see below), whose sum is σ = 3090353760000. Its totient is φ = 402505878528.

The previous prime is 1221805783399. The next prime is 1221805783417. The reversal of 1221805783416 is 6143875081221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221805783417) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 738280 + ... + 1728776.

It is an arithmetic number, because the mean of its divisors is an integer number (48286777500).

Almost surely, 2^{1221805783416} is an apocalyptic number.

It is an amenable number.

1221805783416 is an abundant number, since it is smaller than the sum of its proper divisors (1868547976584).

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

1221805783416 is a wasteful number, since it uses less digits than its factorization.

1221805783416 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 991108 (or 991104 counting only the distinct ones).

The product of its (nonzero) digits is 645120, while the sum is 48.

The spelling of 1221805783416 in words is "one trillion, two hundred twenty-one billion, eight hundred five million, seven hundred eighty-three thousand, four hundred sixteen".