165858723857 has 4 divisors (see below), whose sum is σ = 175615119396. Its totient is φ = 156102328320.

The previous prime is 165858723851. The next prime is 165858723859. The reversal of 165858723857 is 758327858561.

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 115361443201 + 50497280656 = 339649^2 + 224716^2 .

It is a cyclic number.

It is not a de Polignac number, because 165858723857 - 2⁴ = 165858723841 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 165858723793 and 165858723802.

It is not an unprimeable number, because it can be changed into a prime (165858723851) 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, 4878197744 + ... + 4878197777.

It is an arithmetic number, because the mean of its divisors is an integer number (43903779849).

Almost surely, 2^165858723857 is an apocalyptic number.

165858723857 is a gapful number since it is divisible by the number (17) formed by its first and last digit.

It is an amenable number.

165858723857 is a deficient number, since it is larger than the sum of its proper divisors (9756395539).

165858723857 is an equidigital number, since it uses as much as digits as its factorization.

165858723857 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9756395538.

The product of its digits is 112896000, while the sum is 65.

The spelling of 165858723857 in words is "one hundred sixty-five billion, eight hundred fifty-eight million, seven hundred twenty-three thousand, eight hundred fifty-seven".