2166530581 has 8 divisors (see below), whose sum is σ = 2187531864. Its totient is φ = 2145561600.

The previous prime is 2166530539. The next prime is 2166530593. The reversal of 2166530581 is 1850356612.

It can be written as a sum of positive squares in 4 ways, for example, as 27468081 + 2139062500 = 5241^2 + 46250^2 .

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2166530581 is a prime.

It is a super-2 number, since 2×2166530581² = 9387709516816395122, which contains 22 as substring.

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 2166530581.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2166830581) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 139645 + ... + 154381.

It is an arithmetic number, because the mean of its divisors is an integer number (273441483).

Almost surely, 2^2166530581 is an apocalyptic number.

It is an amenable number.

2166530581 is a deficient number, since it is larger than the sum of its proper divisors (21001283).

2166530581 is a wasteful number, since it uses less digits than its factorization.

2166530581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16151.

The product of its (nonzero) digits is 43200, while the sum is 37.

The square root of 2166530581 is about 46546.0049950584. The cubic root of 2166530581 is about 1293.9622542494.

The spelling of 2166530581 in words is "two billion, one hundred sixty-six million, five hundred thirty thousand, five hundred eighty-one".