247130721 has 12 divisors (see below), whose sum is σ = 369276180. Its totient is φ = 159072480.

The previous prime is 247130713. The next prime is 247130753. The reversal of 247130721 is 127031742.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 131331600 + 115799121 = 11460^2 + 10761^2 .

It is not a de Polignac number, because 247130721 - 2³ = 247130713 is a prime.

It is a super-2 number, since 2×247130721² = 122147186523959682, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (247130021) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 473170 + ... + 473691.

It is an arithmetic number, because the mean of its divisors is an integer number (30773015).

Almost surely, 2^247130721 is an apocalyptic number.

It is an amenable number.

247130721 is a deficient number, since it is larger than the sum of its proper divisors (122145459).

247130721 is a wasteful number, since it uses less digits than its factorization.

247130721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 946896 (or 946893 counting only the distinct ones).

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

The square root of 247130721 is about 15720.3918844283. The cubic root of 247130721 is about 627.5412022490.

The spelling of 247130721 in words is "two hundred forty-seven million, one hundred thirty thousand, seven hundred twenty-one".