247807721864 has 8 divisors (see below), whose sum is σ = 464639478510. Its totient is φ = 123903860928.

The previous prime is 247807721851. The next prime is 247807721897. The reversal of 247807721864 is 468127708742.

247807721864 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 218341252900 + 29466468964 = 467270^2 + 171658^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is a super-2 number, since 2×247807721864² (a number of 24 digits) contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15487982609 + ... + 15487982624.

Almost surely, 2^247807721864 is an apocalyptic number.

It is an amenable number.

247807721864 is a deficient number, since it is larger than the sum of its proper divisors (216831756646).

247807721864 is a wasteful number, since it uses less digits than its factorization.

247807721864 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30975965239 (or 30975965235 counting only the distinct ones).

The product of its (nonzero) digits is 8429568, while the sum is 56.

The spelling of 247807721864 in words is "two hundred forty-seven billion, eight hundred seven million, seven hundred twenty-one thousand, eight hundred sixty-four".