166505505640 has 32 divisors (see below), whose sum is σ = 387555921000. Its totient is φ = 64305574144.

The previous prime is 166505505631. The next prime is 166505505641. The reversal of 166505505640 is 46505505661.

It can be written as a sum of positive squares in 4 ways, for example, as 151739853444 + 14765652196 = 389538^2 + 121514^2 .

It is not an unprimeable number, because it can be changed into a prime (166505505641) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 71768455 + ... + 71770774.

Almost surely, 2^166505505640 is an apocalyptic number.

166505505640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

166505505640 is an abundant number, since it is smaller than the sum of its proper divisors (221050415360).

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

166505505640 is a wasteful number, since it uses less digits than its factorization.

166505505640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 143539269 (or 143539265 counting only the distinct ones).

The product of its (nonzero) digits is 540000, while the sum is 43.

The spelling of 166505505640 in words is "one hundred sixty-six billion, five hundred five million, five hundred five thousand, six hundred forty".