223712721 has 6 divisors (see below), whose sum is σ = 323140610. Its totient is φ = 149141808.

The previous prime is 223712717. The next prime is 223712729. The reversal of 223712721 is 127217322.

223712721 is a `hidden beast` number, since 22 + 371 + 272 + 1 = 666.

It can be written as a sum of positive squares in only one way, i.e., 175271121 + 48441600 = 13239^2 + 6960^2 .

It is not a de Polignac number, because 223712721 - 2² = 223712717 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (223712729) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 12428476 + ... + 12428493.

Almost surely, 2^223712721 is an apocalyptic number.

It is an amenable number.

223712721 is a deficient number, since it is larger than the sum of its proper divisors (99427889).

223712721 is a wasteful number, since it uses less digits than its factorization.

223712721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24856975 (or 24856972 counting only the distinct ones).

The product of its digits is 2352, while the sum is 27.

The square root of 223712721 is about 14957.0291502023. The cubic root of 223712721 is about 607.0580558523.

The spelling of 223712721 in words is "two hundred twenty-three million, seven hundred twelve thousand, seven hundred twenty-one".