8857516721 has 4 divisors (see below), whose sum is σ = 9024639732. Its totient is φ = 8690393712.

The previous prime is 8857516699. The next prime is 8857516751. The reversal of 8857516721 is 1276157588.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 5442750625 + 3414766096 = 73775^2 + 58436^2 .

It is a cyclic number.

It is not a de Polignac number, because 8857516721 - 2¹⁸ = 8857254577 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 8857516721.

It is not an unprimeable number, because it can be changed into a prime (8857516751) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 83561426 + ... + 83561531.

It is an arithmetic number, because the mean of its divisors is an integer number (2256159933).

Almost surely, 2^8857516721 is an apocalyptic number.

It is an amenable number.

8857516721 is a deficient number, since it is larger than the sum of its proper divisors (167123011).

8857516721 is a wasteful number, since it uses less digits than its factorization.

8857516721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 167123010.

The product of its digits is 940800, while the sum is 50.

The square root of 8857516721 is about 94114.3810530569. The cubic root of 8857516721 is about 2069.0484491293.

The spelling of 8857516721 in words is "eight billion, eight hundred fifty-seven million, five hundred sixteen thousand, seven hundred twenty-one".