121564042778 has 8 divisors (see below), whose sum is σ = 182365824180. Its totient is φ = 60775434720.

The previous prime is 121564042771. The next prime is 121564042819. The reversal of 121564042778 is 877240465121.

121564042778 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 120258449089 + 1305593689 = 346783^2 + 36133^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not an unprimeable number, because it can be changed into a prime (121564042771) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3270233 + ... + 3307196.

Almost surely, 2^121564042778 is an apocalyptic number.

121564042778 is a deficient number, since it is larger than the sum of its proper divisors (60801781402).

121564042778 is an equidigital number, since it uses as much as digits as its factorization.

121564042778 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6586672.

The product of its (nonzero) digits is 752640, while the sum is 47.

The spelling of 121564042778 in words is "one hundred twenty-one billion, five hundred sixty-four million, forty-two thousand, seven hundred seventy-eight".