66147878057 has 4 divisors (see below), whose sum is σ = 66171530436. Its totient is φ = 66124225680.

The previous prime is 66147878021. The next prime is 66147878059. The reversal of 66147878057 is 75087874166.

66147878057 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 46519587856 + 19628290201 = 215684^2 + 140101^2 .

It is a cyclic number.

It is not a de Polignac number, because 66147878057 - 2¹⁴ = 66147861673 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 66147877987 and 66147878005.

It is not an unprimeable number, because it can be changed into a prime (66147878059) 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, 11821994 + ... + 11827587.

It is an arithmetic number, because the mean of its divisors is an integer number (16542882609).

Almost surely, 2^66147878057 is an apocalyptic number.

It is an amenable number.

66147878057 is a deficient number, since it is larger than the sum of its proper divisors (23652379).

66147878057 is a wasteful number, since it uses less digits than its factorization.

66147878057 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23652378.

The product of its (nonzero) digits is 15805440, while the sum is 59.

The spelling of 66147878057 in words is "sixty-six billion, one hundred forty-seven million, eight hundred seventy-eight thousand, fifty-seven".