165825558381 has 24 divisors (see below), whose sum is σ = 257792916864. Its totient is φ = 94538586240.

The previous prime is 165825558377. The next prime is 165825558419. The reversal of 165825558381 is 183855528561.

It is not a de Polignac number, because 165825558381 - 2² = 165825558377 is a prime.

It is a super-2 number, since 2×165825558381² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (165825558881) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1238965 + ... + 1366266.

It is an arithmetic number, because the mean of its divisors is an integer number (10741371536).

Almost surely, 2^165825558381 is an apocalyptic number.

It is an amenable number.

165825558381 is a deficient number, since it is larger than the sum of its proper divisors (91967358483).

165825558381 is a wasteful number, since it uses less digits than its factorization.

165825558381 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2605681 (or 2605674 counting only the distinct ones).

The product of its digits is 11520000, while the sum is 57.

It can be divided in two parts, 165825 and 558381, that added together give a triangular number (724206 = T₁₂₀₃).

The spelling of 165825558381 in words is "one hundred sixty-five billion, eight hundred twenty-five million, five hundred fifty-eight thousand, three hundred eighty-one".