247720745 has 4 divisors (see below), whose sum is σ = 297264900. Its totient is φ = 198176592.

The previous prime is 247720709. The next prime is 247720751. The reversal of 247720745 is 547027742.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 547027742 = 2 ⋅273513871.

It can be written as a sum of positive squares in 2 ways, for example, as 88153321 + 159567424 = 9389^2 + 12632^2 .

It is a cyclic number.

It is not a de Polignac number, because 247720745 - 2²⁰ = 246672169 is a prime.

It is a super-2 number, since 2×247720745² = 122731135006710050, which contains 22 as substring.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 247720699 and 247720708.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 24772070 + ... + 24772079.

It is an arithmetic number, because the mean of its divisors is an integer number (74316225).

Almost surely, 2^247720745 is an apocalyptic number.

It is an amenable number.

247720745 is a deficient number, since it is larger than the sum of its proper divisors (49544155).

247720745 is an equidigital number, since it uses as much as digits as its factorization.

247720745 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 49544154.

The product of its (nonzero) digits is 109760, while the sum is 38.

The square root of 247720745 is about 15739.1468955595. The cubic root of 247720745 is about 628.0402230245.

The spelling of 247720745 in words is "two hundred forty-seven million, seven hundred twenty thousand, seven hundred forty-five".