1221199999078 has 16 divisors (see below), whose sum is σ = 1928767857840. Its totient is φ = 578295957600.

The previous prime is 1221199999073. The next prime is 1221199999079. The reversal of 1221199999078 is 8709999911221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221199999073) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4511193 + ... + 4774228.

It is an arithmetic number, because the mean of its divisors is an integer number (120547991115).

Almost surely, 2^{1221199999078} is an apocalyptic number.

1221199999078 is a deficient number, since it is larger than the sum of its proper divisors (707567858762).

1221199999078 is a wasteful number, since it uses less digits than its factorization.

1221199999078 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9288903.

The product of its (nonzero) digits is 13226976, while the sum is 67.

The spelling of 1221199999078 in words is "one trillion, two hundred twenty-one billion, one hundred ninety-nine million, nine hundred ninety-nine thousand, seventy-eight".