165865067550 has 768 divisors, whose sum is σ = 587962368000. Its totient is φ = 33443020800.

The previous prime is 165865067539. The next prime is 165865067567. The reversal of 165865067550 is 55760568561.

165865067550 is a `hidden beast` number, since 1 + 6 + 5 + 86 + 5 + 0 + 6 + 7 + 550 = 666.

It is a super-2 number, since 2×165865067550² (a number of 23 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 383 ways as a sum of consecutive naturals, for example, 369409726 + ... + 369410174.

It is an arithmetic number, because the mean of its divisors is an integer number (765576000).

Almost surely, 2^165865067550 is an apocalyptic number.

165865067550 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 165865067550, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (293981184000).

165865067550 is an abundant number, since it is smaller than the sum of its proper divisors (422097300450).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

165865067550 is a wasteful number, since it uses less digits than its factorization.

165865067550 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 618 (or 607 counting only the distinct ones).

The product of its (nonzero) digits is 7560000, while the sum is 54.

The spelling of 165865067550 in words is "one hundred sixty-five billion, eight hundred sixty-five million, sixty-seven thousand, five hundred fifty".