101666889 has 9 divisors (see below), whose sum is σ = 146895879. Its totient is φ = 67757760.

The previous prime is 101666867. The next prime is 101666899. The reversal of 101666889 is 988666101.

It is a happy number.

The square root of 101666889 is 10083.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 76265289 + 25401600 = 8733^2 + 5040^2 .

It is a tau number, because it is divible by the number of its divisors (9).

It is not a de Polignac number, because 101666889 - 2⁵ = 101666857 is a prime.

It is not an unprimeable number, because it can be changed into a prime (101666899) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 28569 + ... + 31929.

Almost surely, 2^101666889 is an apocalyptic number.

101666889 is the 10083-rd square number.

101666889 is the 5042-nd centered octagonal number.

It is an amenable number.

101666889 is a deficient number, since it is larger than the sum of its proper divisors (45228990).

101666889 is an frugal number, since it uses more digits than its factorization.

101666889 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6728 (or 3364 counting only the distinct ones).

The product of its (nonzero) digits is 124416, while the sum is 45.

The cubic root of 101666889 is about 466.7236893472.

The spelling of 101666889 in words is "one hundred one million, six hundred sixty-six thousand, eight hundred eighty-nine".