166111511665020 has 288 divisors, whose sum is σ = 496491087568896. Its totient is φ = 41487748300800.

The previous prime is 166111511665013. The next prime is 166111511665049. The reversal of 166111511665020 is 20566115111661.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 4055337340 + ... + 4055378300.

It is an arithmetic number, because the mean of its divisors is an integer number (1723927387392).

Almost surely, 2^{166111511665020} is an apocalyptic number.

166111511665020 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 166111511665020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (248245543784448).

166111511665020 is an abundant number, since it is smaller than the sum of its proper divisors (330379575903876).

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

166111511665020 is a wasteful number, since it uses less digits than its factorization.

166111511665020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42141 (or 42122 counting only the distinct ones).

The product of its (nonzero) digits is 64800, while the sum is 42.

Adding to 166111511665020 its reverse (20566115111661), we get a palindrome (186677626776681).

The spelling of 166111511665020 in words is "one hundred sixty-six trillion, one hundred eleven billion, five hundred eleven million, six hundred sixty-five thousand, twenty".