165661426560 has 512 divisors, whose sum is σ = 642629376000. Its totient is φ = 36215832576.

The previous prime is 165661426543. The next prime is 165661426591. The reversal of 165661426560 is 65624166561.

It is a Harshad number since it is a multiple of its sum of digits (48).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 15141412 + ... + 15152348.

It is an arithmetic number, because the mean of its divisors is an integer number (1255135500).

Almost surely, 2^165661426560 is an apocalyptic number.

165661426560 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 165661426560, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (321314688000).

165661426560 is an abundant number, since it is smaller than the sum of its proper divisors (476967949440).

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

165661426560 is a wasteful number, since it uses less digits than its factorization.

165661426560 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11003 (or 10977 counting only the distinct ones).

The product of its (nonzero) digits is 1555200, while the sum is 48.

The spelling of 165661426560 in words is "one hundred sixty-five billion, six hundred sixty-one million, four hundred twenty-six thousand, five hundred sixty".