166861752553 has 4 divisors (see below), whose sum is σ = 176677149780. Its totient is φ = 157046355328.

The previous prime is 166861752511. The next prime is 166861752581. The reversal of 166861752553 is 355257168661.

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

It can be written as a sum of positive squares in 2 ways, for example, as 47590295104 + 119271457449 = 218152^2 + 345357^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-166861752553 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 166861752494 and 166861752503.

It is not an unprimeable number, because it can be changed into a prime (166861755553) 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, 4907698588 + ... + 4907698621.

It is an arithmetic number, because the mean of its divisors is an integer number (44169287445).

Almost surely, 2^166861752553 is an apocalyptic number.

It is an amenable number.

166861752553 is a deficient number, since it is larger than the sum of its proper divisors (9815397227).

166861752553 is an equidigital number, since it uses as much as digits as its factorization.

166861752553 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9815397226.

The product of its digits is 9072000, while the sum is 55.

The spelling of 166861752553 in words is "one hundred sixty-six billion, eight hundred sixty-one million, seven hundred fifty-two thousand, five hundred fifty-three".