165563126820 has 1728 divisors, whose sum is σ = 728044402176. Its totient is φ = 30636195840.

The previous prime is 165563126819. The next prime is 165563126843. The reversal of 165563126820 is 28621365561.

165563126820 is a `hidden beast` number, since 1 + 6 + 5 + 5 + 631 + 2 + 6 + 8 + 2 + 0 = 666.

It is a super-2 number, since 2×165563126820² (a number of 23 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a polite number, since it can be written in 575 ways as a sum of consecutive naturals, for example, 2714149590 + ... + 2714149650.

It is an arithmetic number, because the mean of its divisors is an integer number (421321992).

Almost surely, 2^165563126820 is an apocalyptic number.

165563126820 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 165563126820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (364022201088).

165563126820 is an abundant number, since it is smaller than the sum of its proper divisors (562481275356).

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

165563126820 is a wasteful number, since it uses less digits than its factorization.

165563126820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 160 (or 127 counting only the distinct ones).

The product of its (nonzero) digits is 518400, while the sum is 45.

The spelling of 165563126820 in words is "one hundred sixty-five billion, five hundred sixty-three million, one hundred twenty-six thousand, eight hundred twenty".