28116917761 has 9 divisors (see below), whose sum is σ = 28519773321. Its totient is φ = 27719681472.

The previous prime is 28116917683. The next prime is 28116917767. The reversal of 28116917761 is 16771961182.

The square root of 28116917761 is 167681.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 4 ways, for example, as 40564161 + 28076353600 = 6369^2 + 167560^2 .

It is not a de Polignac number, because 28116917761 - 2¹¹ = 28116915713 is a prime.

It is a super-2 number, since 2×28116917761² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28116917767) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 12239565 + ... + 12241861.

Almost surely, 2^28116917761 is an apocalyptic number.

28116917761 is the 167681-st square number.

28116917761 is the 83841-st centered octagonal number.

It is an amenable number.

28116917761 is a deficient number, since it is larger than the sum of its proper divisors (402855560).

28116917761 is an frugal number, since it uses more digits than its factorization.

28116917761 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4740 (or 2370 counting only the distinct ones).

The product of its digits is 254016, while the sum is 49.

Multiplying 28116917761 by its sum of digits (49), we get a square (1377728970289 = 1173767²).

The spelling of 28116917761 in words is "twenty-eight billion, one hundred sixteen million, nine hundred seventeen thousand, seven hundred sixty-one".