166665253281811 has 4 divisors (see below), whose sum is σ = 166666556836312. Its totient is φ = 166663949727312.

The previous prime is 166665253281731. The next prime is 166665253281847. The reversal of 166665253281811 is 118182352566661.

166665253281811 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 166665253281811 - 2⁹ = 166665253281299 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 166665253281811.

It is not an unprimeable number, because it can be changed into a prime (166665253381811) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 651585450 + ... + 651841183.

It is an arithmetic number, because the mean of its divisors is an integer number (41666639209078).

Almost surely, 2^{166665253281811} is an apocalyptic number.

166665253281811 is a deficient number, since it is larger than the sum of its proper divisors (1303554501).

166665253281811 is a wasteful number, since it uses less digits than its factorization.

166665253281811 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1303554500.

The product of its digits is 24883200, while the sum is 61.

The spelling of 166665253281811 in words is "one hundred sixty-six trillion, six hundred sixty-five billion, two hundred fifty-three million, two hundred eighty-one thousand, eight hundred eleven".