166505663515 has 16 divisors (see below), whose sum is σ = 211608191232. Its totient is φ = 125340493824.

The previous prime is 166505663507. The next prime is 166505663531. The reversal of 166505663515 is 515366505661.

It is a cyclic number.

It is not a de Polignac number, because 166505663515 - 2³ = 166505663507 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 157747 + ... + 598243.

It is an arithmetic number, because the mean of its divisors is an integer number (13225511952).

Almost surely, 2^166505663515 is an apocalyptic number.

166505663515 is a deficient number, since it is larger than the sum of its proper divisors (45102527717).

166505663515 is a wasteful number, since it uses less digits than its factorization.

166505663515 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 444966.

The product of its (nonzero) digits is 2430000, while the sum is 49.

The spelling of 166505663515 in words is "one hundred sixty-six billion, five hundred five million, six hundred sixty-three thousand, five hundred fifteen".