78723528321 has 4 divisors (see below), whose sum is σ = 104964704432. Its totient is φ = 52482352212.

The previous prime is 78723528313. The next prime is 78723528349. The reversal of 78723528321 is 12382532787.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 78723528321 - 2³ = 78723528313 is a prime.

It is a super-2 number, since 2×78723528321² (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 (78723528371) 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, 13120588051 + ... + 13120588056.

It is an arithmetic number, because the mean of its divisors is an integer number (26241176108).

Almost surely, 2^78723528321 is an apocalyptic number.

It is an amenable number.

78723528321 is a deficient number, since it is larger than the sum of its proper divisors (26241176111).

78723528321 is a wasteful number, since it uses less digits than its factorization.

78723528321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26241176110.

The product of its digits is 1128960, while the sum is 48.

The spelling of 78723528321 in words is "seventy-eight billion, seven hundred twenty-three million, five hundred twenty-eight thousand, three hundred twenty-one".