78223572578 has 6 divisors (see below), whose sum is σ = 117335952171. Its totient is φ = 39111588522.

The previous prime is 78223572571. The next prime is 78223572599. The reversal of 78223572578 is 87527532287.

It can be written as a sum of positive squares in only one way, i.e., 39111786289 + 39111786289 = 197767^2 + 197767^2 .

It is an ABA number since it can be written as A⋅B^A, here for A=2, B=197767.

It is a super-2 number, since 2×78223572578² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (78223572571) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 296651 + ... + 494417.

Almost surely, 2^78223572578 is an apocalyptic number.

78223572578 is a deficient number, since it is larger than the sum of its proper divisors (39112379593).

78223572578 is an frugal number, since it uses more digits than its factorization.

78223572578 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 395536 (or 197769 counting only the distinct ones).

The product of its digits is 13171200, while the sum is 56.

The spelling of 78223572578 in words is "seventy-eight billion, two hundred twenty-three million, five hundred seventy-two thousand, five hundred seventy-eight".