220729 has 4 divisors (see below), whose sum is σ = 222976. Its totient is φ = 218484.

The previous prime is 220721. The next prime is 220747. The reversal of 220729 is 927022.

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, and also an emirpimes, since its reverse is a distinct semiprime: 927022 = 2 ⋅463511.

It is a cyclic number.

It is not a de Polignac number, because 220729 - 2³ = 220721 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (220721) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 969 + ... + 1174.

It is an arithmetic number, because the mean of its divisors is an integer number (55744).

It is a Poulet number, since it divides 2²²⁰⁷²⁸-1.

2²²⁰⁷²⁹ is an apocalyptic number.

It is an amenable number.

220729 is a deficient number, since it is larger than the sum of its proper divisors (2247).

220729 is a wasteful number, since it uses less digits than its factorization.

220729 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2246.

The product of its (nonzero) digits is 504, while the sum is 22.

The square root of 220729 is about 469.8180498874. The cubic root of 220729 is about 60.4347131715.

It can be divided in two parts, 220 and 729, that added together give a palindrome (949).

The spelling of 220729 in words is "two hundred twenty thousand, seven hundred twenty-nine".