221143581 has 16 divisors (see below), whose sum is σ = 329457600. Its totient is φ = 146602224.

The previous prime is 221143543. The next prime is 221143609. The reversal of 221143581 is 185341122.

221143581 is a `hidden beast` number, since 221 + 1 + 435 + 8 + 1 = 666.

221143581 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 221143581 - 2²³ = 212754973 is a prime.

It is a super-2 number, since 2×221143581² = 97808966835007122, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221143541) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 18046 + ... + 27711.

It is an arithmetic number, because the mean of its divisors is an integer number (20591100).

Almost surely, 2^221143581 is an apocalyptic number.

It is an amenable number.

221143581 is a deficient number, since it is larger than the sum of its proper divisors (108314019).

221143581 is a wasteful number, since it uses less digits than its factorization.

221143581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 45945 (or 45939 counting only the distinct ones).

The product of its digits is 1920, while the sum is 27.

The square root of 221143581 is about 14870.8971148347. The cubic root of 221143581 is about 604.7252637794.

The spelling of 221143581 in words is "two hundred twenty-one million, one hundred forty-three thousand, five hundred eighty-one".