161685523583 has 4 divisors (see below), whose sum is σ = 162397794840. Its totient is φ = 160973252328.

The previous prime is 161685523561. The next prime is 161685523591. The reversal of 161685523583 is 385325586161.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 161685523583 - 2¹⁴ = 161685507199 is a prime.

It is a super-2 number, since 2×161685523583² (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 (161615523583) 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, 356135288 + ... + 356135741.

It is an arithmetic number, because the mean of its divisors is an integer number (40599448710).

Almost surely, 2^161685523583 is an apocalyptic number.

161685523583 is a deficient number, since it is larger than the sum of its proper divisors (712271257).

161685523583 is an equidigital number, since it uses as much as digits as its factorization.

161685523583 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 712271256.

The product of its digits is 5184000, while the sum is 53.

The spelling of 161685523583 in words is "one hundred sixty-one billion, six hundred eighty-five million, five hundred twenty-three thousand, five hundred eighty-three".