221812723 has 6 divisors (see below), whose sum is σ = 243810812. Its totient is φ = 201647820.

The previous prime is 221812709. The next prime is 221812729. The reversal of 221812723 is 327218122.

It is a de Polignac number, because none of the positive numbers 2^k-221812723 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 221812691 and 221812700.

It is not an unprimeable number, because it can be changed into a prime (221812729) 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 5 ways as a sum of consecutive naturals, for example, 916461 + ... + 916702.

Almost surely, 2^221812723 is an apocalyptic number.

221812723 is a deficient number, since it is larger than the sum of its proper divisors (21998089).

221812723 is a wasteful number, since it uses less digits than its factorization.

221812723 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1833185 (or 1833174 counting only the distinct ones).

The product of its digits is 2688, while the sum is 28.

The square root of 221812723 is about 14893.3784951568. The cubic root of 221812723 is about 605.3345807742.

It can be divided in two parts, 2218 and 12723, that added together give a palindrome (14941).

The spelling of 221812723 in words is "two hundred twenty-one million, eight hundred twelve thousand, seven hundred twenty-three".