85215955778 has 18 divisors (see below), whose sum is σ = 128770254963. Its totient is φ = 42294843300.

The previous prime is 85215955771. The next prime is 85215955787. The reversal of 85215955778 is 87755951258.

It can be written as a sum of positive squares in only one way, i.e., 42607977889 + 42607977889 = 206417^2 + 206417^2 .

It is an ABA number since it can be written as A⋅B^A, here for A=2, B=206417.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 85215955778.

It is not an unprimeable number, because it can be changed into a prime (85215955771) 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 8 ways as a sum of consecutive naturals, for example, 62337251 + ... + 62338617.

Almost surely, 2^85215955778 is an apocalyptic number.

85215955778 is a deficient number, since it is larger than the sum of its proper divisors (43554299185).

85215955778 is an frugal number, since it uses more digits than its factorization.

85215955778 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3038 (or 1520 counting only the distinct ones).

The product of its digits is 35280000, while the sum is 62.

The spelling of 85215955778 in words is "eighty-five billion, two hundred fifteen million, nine hundred fifty-five thousand, seven hundred seventy-eight".