247224821 has 2 divisors, whose sum is σ = 247224822. Its totient is φ = 247224820.

The previous prime is 247224749. The next prime is 247224839. The reversal of 247224821 is 128422742.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 212284900 + 34939921 = 14570^2 + 5911^2 .

It is a cyclic number.

It is not a de Polignac number, because 247224821 - 2¹⁰ = 247223797 is a prime.

It is a super-3 number, since 3×247224821³ (a number of 26 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (247224851) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 123612410 + 123612411.

It is an arithmetic number, because the mean of its divisors is an integer number (123612411).

Almost surely, 2^247224821 is an apocalyptic number.

It is an amenable number.

247224821 is a deficient number, since it is larger than the sum of its proper divisors (1).

247224821 is an equidigital number, since it uses as much as digits as its factorization.

247224821 is an evil number, because the sum of its binary digits is even.

The product of its digits is 14336, while the sum is 32.

The square root of 247224821 is about 15723.3845275119. The cubic root of 247224821 is about 627.6208417928.

The spelling of 247224821 in words is "two hundred forty-seven million, two hundred twenty-four thousand, eight hundred twenty-one".