220781 has 4 divisors (see below), whose sum is σ = 240864. Its totient is φ = 200700.

The previous prime is 220771. The next prime is 220783. The reversal of 220781 is 187022.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 220781 - 2¹⁰ = 219757 is a prime.

It is a super-2 number, since 2×220781² = 97488499922, which contains 22 as substring.

It is a pancake number, because a pancake can be divided into 220781 parts by 664 straight cuts.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (220783) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10025 + ... + 10046.

It is an arithmetic number, because the mean of its divisors is an integer number (60216).

2²²⁰⁷⁸¹ is an apocalyptic number.

It is an amenable number.

220781 is a deficient number, since it is larger than the sum of its proper divisors (20083).

220781 is a wasteful number, since it uses less digits than its factorization.

220781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20082.

The product of its (nonzero) digits is 224, while the sum is 20.

The square root of 220781 is about 469.8733872013. The cubic root of 220781 is about 60.4394585959.

It can be divided in two parts, 220 and 781, that added together give a palindrome (1001).

The spelling of 220781 in words is "two hundred twenty thousand, seven hundred eighty-one".