8637720641 has 6 divisors (see below), whose sum is σ = 9494354226. Its totient is φ = 7852473200.

The previous prime is 8637720629. The next prime is 8637720643. The reversal of 8637720641 is 1460277368.

It can be written as a sum of positive squares in only one way, i.e., 8114226241 + 523494400 = 90079^2 + 22880^2 .

It is a de Polignac number, because none of the positive numbers 2^k-8637720641 is a prime.

It is a super-3 number, since 3×8637720641³ (a number of 31 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 8637720592 and 8637720601.

It is not an unprimeable number, because it can be changed into a prime (8637720643) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 35692940 + ... + 35693181.

It is an arithmetic number, because the mean of its divisors is an integer number (1582392371).

Almost surely, 2^8637720641 is an apocalyptic number.

It is an amenable number.

8637720641 is a deficient number, since it is larger than the sum of its proper divisors (856633585).

8637720641 is a wasteful number, since it uses less digits than its factorization.

8637720641 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 71386143 (or 71386132 counting only the distinct ones).

The product of its (nonzero) digits is 338688, while the sum is 44.

The square root of 8637720641 is about 92939.3385009814. The cubic root of 8637720641 is about 2051.7906734256.

The spelling of 8637720641 in words is "eight billion, six hundred thirty-seven million, seven hundred twenty thousand, six hundred forty-one".