166542889 has 4 divisors (see below), whose sum is σ = 168259924. Its totient is φ = 164825856.

The previous prime is 166542877. The next prime is 166542917. The reversal of 166542889 is 988245661.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 988245661 = 13 ⋅76018897.

It can be written as a sum of positive squares in 2 ways, for example, as 122877225 + 43665664 = 11085^2 + 6608^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-166542889 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (166542869) 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, 858372 + ... + 858565.

It is an arithmetic number, because the mean of its divisors is an integer number (42064981).

Almost surely, 2^166542889 is an apocalyptic number.

It is an amenable number.

166542889 is a deficient number, since it is larger than the sum of its proper divisors (1717035).

166542889 is an equidigital number, since it uses as much as digits as its factorization.

166542889 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1717034.

The product of its digits is 829440, while the sum is 49.

The square root of 166542889 is about 12905.1497085466. The cubic root of 166542889 is about 550.1849394594.

The spelling of 166542889 in words is "one hundred sixty-six million, five hundred forty-two thousand, eight hundred eighty-nine".