166406204765 has 4 divisors (see below), whose sum is σ = 199687445724. Its totient is φ = 133124963808.

The previous prime is 166406204747. The next prime is 166406204819. The reversal of 166406204765 is 567402604661.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 567402604661 = 18049 ⋅31436789.

It can be written as a sum of positive squares in 2 ways, for example, as 33510231364 + 132895973401 = 183058^2 + 364549^2 .

It is a cyclic number.

It is not a de Polignac number, because 166406204765 - 2¹⁰ = 166406203741 is a prime.

It is a super-2 number, since 2×166406204765² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 16640620472 + ... + 16640620481.

It is an arithmetic number, because the mean of its divisors is an integer number (49921861431).

Almost surely, 2^166406204765 is an apocalyptic number.

It is an amenable number.

166406204765 is a deficient number, since it is larger than the sum of its proper divisors (33281240959).

166406204765 is an equidigital number, since it uses as much as digits as its factorization.

166406204765 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33281240958.

The product of its (nonzero) digits is 1451520, while the sum is 47.

The spelling of 166406204765 in words is "one hundred sixty-six billion, four hundred six million, two hundred four thousand, seven hundred sixty-five".