247740725261 has 4 divisors (see below), whose sum is σ = 247755801024. Its totient is φ = 247725649500.

The previous prime is 247740725257. The next prime is 247740725303. The reversal of 247740725261 is 162527047742.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 162527047742 = 2 ⋅81263523871.

It is a cyclic number.

It is not a de Polignac number, because 247740725261 - 2² = 247740725257 is a prime.

It is a super-2 number, since 2×247740725261² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (247740725251) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7513205 + ... + 7546106.

It is an arithmetic number, because the mean of its divisors is an integer number (61938950256).

Almost surely, 2^247740725261 is an apocalyptic number.

It is an amenable number.

247740725261 is a deficient number, since it is larger than the sum of its proper divisors (15075763).

247740725261 is a wasteful number, since it uses less digits than its factorization.

247740725261 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15075762.

The product of its (nonzero) digits is 1317120, while the sum is 47.

The spelling of 247740725261 in words is "two hundred forty-seven billion, seven hundred forty million, seven hundred twenty-five thousand, two hundred sixty-one".