163685781373 has 4 divisors (see below), whose sum is σ = 163730865088. Its totient is φ = 163640697660.

The previous prime is 163685781313. The next prime is 163685781377. The reversal of 163685781373 is 373187586361.

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, and also an emirpimes, since its reverse is a distinct semiprime: 373187586361 = 76481 ⋅4879481.

It is a cyclic number.

It is not a de Polignac number, because 163685781373 - 2⁹ = 163685780861 is a prime.

It is a super-4 number, since 4×163685781373⁴ (a number of 46 digits) contains 4444 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 (163685781377) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 22536411 + ... + 22543672.

It is an arithmetic number, because the mean of its divisors is an integer number (40932716272).

Almost surely, 2^163685781373 is an apocalyptic number.

It is an amenable number.

163685781373 is a deficient number, since it is larger than the sum of its proper divisors (45083715).

163685781373 is an equidigital number, since it uses as much as digits as its factorization.

163685781373 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 45083714.

The product of its digits is 15240960, while the sum is 58.

The spelling of 163685781373 in words is "one hundred sixty-three billion, six hundred eighty-five million, seven hundred eighty-one thousand, three hundred seventy-three".