78221012189 has 4 divisors (see below), whose sum is σ = 78264445980. Its totient is φ = 78177578400.

The previous prime is 78221012183. The next prime is 78221012197. The reversal of 78221012189 is 98121012287.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 49713391225 + 28507620964 = 222965^2 + 168842^2 .

It is a cyclic number.

It is not a de Polignac number, because 78221012189 - 2⁴ = 78221012173 is a prime.

It is a super-2 number, since 2×78221012189² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78221012183) 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, 21714194 + ... + 21717795.

It is an arithmetic number, because the mean of its divisors is an integer number (19566111495).

Almost surely, 2^78221012189 is an apocalyptic number.

It is an amenable number.

78221012189 is a deficient number, since it is larger than the sum of its proper divisors (43433791).

78221012189 is a wasteful number, since it uses less digits than its factorization.

78221012189 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 43433790.

The product of its (nonzero) digits is 32256, while the sum is 41.

The spelling of 78221012189 in words is "seventy-eight billion, two hundred twenty-one million, twelve thousand, one hundred eighty-nine".