224745721 has 4 divisors (see below), whose sum is σ = 225078372. Its totient is φ = 224413072.

The previous prime is 224745713. The next prime is 224745727. The reversal of 224745721 is 127547422.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 127547422 = 2 ⋅63773711.

It can be written as a sum of positive squares in 2 ways, for example, as 209815225 + 14930496 = 14485^2 + 3864^2 .

It is a cyclic number.

It is not a de Polignac number, because 224745721 - 2³ = 224745713 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (224745727) 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, 165310 + ... + 166663.

It is an arithmetic number, because the mean of its divisors is an integer number (56269593).

Almost surely, 2^224745721 is an apocalyptic number.

It is an amenable number.

224745721 is a deficient number, since it is larger than the sum of its proper divisors (332651).

224745721 is an equidigital number, since it uses as much as digits as its factorization.

224745721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 332650.

The product of its digits is 31360, while the sum is 34.

The square root of 224745721 is about 14991.5216372455. The cubic root of 224745721 is about 607.9909907844.

The spelling of 224745721 in words is "two hundred twenty-four million, seven hundred forty-five thousand, seven hundred twenty-one".