2166386581 has 8 divisors (see below), whose sum is σ = 2189894400. Its totient is φ = 2142999600.

The previous prime is 2166386561. The next prime is 2166386627. The reversal of 2166386581 is 1856836612.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 2166386581 - 2⁵ = 2166386549 is a prime.

It is a super-2 number, since 2×2166386581² = 9386461636673739122, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2166386561) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6075 + ... + 66103.

It is an arithmetic number, because the mean of its divisors is an integer number (273736800).

Almost surely, 2^2166386581 is an apocalyptic number.

It is an amenable number.

2166386581 is a deficient number, since it is larger than the sum of its proper divisors (23507819).

2166386581 is a wasteful number, since it uses less digits than its factorization.

2166386581 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 60419.

The product of its digits is 414720, while the sum is 46.

The square root of 2166386581 is about 46544.4581126475. The cubic root of 2166386581 is about 1293.9335855729.

The spelling of 2166386581 in words is "two billion, one hundred sixty-six million, three hundred eighty-six thousand, five hundred eighty-one".