220843981 has 4 divisors (see below), whose sum is σ = 220874364. Its totient is φ = 220813600.

The previous prime is 220843979. The next prime is 220844003. The reversal of 220843981 is 189348022.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 75255625 + 145588356 = 8675^2 + 12066^2 .

It is a cyclic number.

It is not a de Polignac number, because 220843981 - 2¹ = 220843979 is a prime.

It is a super-2 number, since 2×220843981² = 97544127887856722, 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 220843981.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (220843901) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2871 + ... + 21211.

It is an arithmetic number, because the mean of its divisors is an integer number (55218591).

Almost surely, 2^220843981 is an apocalyptic number.

It is an amenable number.

220843981 is a deficient number, since it is larger than the sum of its proper divisors (30383).

220843981 is a wasteful number, since it uses less digits than its factorization.

220843981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30382.

The product of its (nonzero) digits is 27648, while the sum is 37.

The square root of 220843981 is about 14860.8203340192. The cubic root of 220843981 is about 604.4520512850.

The spelling of 220843981 in words is "two hundred twenty million, eight hundred forty-three thousand, nine hundred eighty-one".