78521972807 has 4 divisors (see below), whose sum is σ = 78617615496. Its totient is φ = 78426330120.

The previous prime is 78521972701. The next prime is 78521972827. The reversal of 78521972807 is 70827912587.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 70827912587 = 19 ⋅3727784873.

It is a cyclic number.

It is not a de Polignac number, because 78521972807 - 2¹⁶ = 78521907271 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78521972827) 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, 47820113 + ... + 47821754.

It is an arithmetic number, because the mean of its divisors is an integer number (19654403874).

Almost surely, 2^78521972807 is an apocalyptic number.

78521972807 is a deficient number, since it is larger than the sum of its proper divisors (95642689).

78521972807 is an equidigital number, since it uses as much as digits as its factorization.

78521972807 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 95642688.

The product of its (nonzero) digits is 3951360, while the sum is 56.

The spelling of 78521972807 in words is "seventy-eight billion, five hundred twenty-one million, nine hundred seventy-two thousand, eight hundred seven".