8521727617661 has 4 divisors (see below), whose sum is σ = 8522887201500. Its totient is φ = 8520568033824.

The previous prime is 8521727617621. The next prime is 8521727617693. The reversal of 8521727617661 is 1667167271258.

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 6641521723225 + 1880205894436 = 2577115^2 + 1371206^2 .

It is a cyclic number.

It is not a de Polignac number, because 8521727617661 - 2²⁶ = 8521660508797 is a prime.

It is a super-2 number, since 2×8521727617661² (a number of 27 digits) contains 22 as substring.

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 8521727617661.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (8521727617621) 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, 579780896 + ... + 579795593.

It is an arithmetic number, because the mean of its divisors is an integer number (2130721800375).

Almost surely, 2^{8521727617661} is an apocalyptic number.

It is an amenable number.

8521727617661 is a deficient number, since it is larger than the sum of its proper divisors (1159583839).

8521727617661 is a wasteful number, since it uses less digits than its factorization.

8521727617661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1159583838.

The product of its digits is 11854080, while the sum is 59.

The spelling of 8521727617661 in words is "eight trillion, five hundred twenty-one billion, seven hundred twenty-seven million, six hundred seventeen thousand, six hundred sixty-one".