78852570821 has 4 divisors (see below), whose sum is σ = 78869507532. Its totient is φ = 78835634112.

The previous prime is 78852570817. The next prime is 78852570847. The reversal of 78852570821 is 12807525887.

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 44196652900 + 34655917921 = 210230^2 + 186161^2 .

It is a cyclic number.

It is not a de Polignac number, because 78852570821 - 2² = 78852570817 is a prime.

It is a super-2 number, since 2×78852570821² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78852570851) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8461370 + ... + 8470683.

It is an arithmetic number, because the mean of its divisors is an integer number (19717376883).

Almost surely, 2^78852570821 is an apocalyptic number.

It is an amenable number.

78852570821 is a deficient number, since it is larger than the sum of its proper divisors (16936711).

78852570821 is a wasteful number, since it uses less digits than its factorization.

78852570821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16936710.

The product of its (nonzero) digits is 2508800, while the sum is 53.

The spelling of 78852570821 in words is "seventy-eight billion, eight hundred fifty-two million, five hundred seventy thousand, eight hundred twenty-one".