8561985961 has 9 divisors (see below), whose sum is σ = 9096929751. Its totient is φ = 8056859232.

The previous prime is 8561985953. The next prime is 8561985983. The reversal of 8561985961 is 1695891658.

The square root of 8561985961 is 92531.

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

It can be written as a sum of positive squares in only one way, i.e., 6665906025 + 1896079936 = 81645^2 + 43544^2 .

It is not a de Polignac number, because 8561985961 - 2³ = 8561985953 is a prime.

It is a super-2 number, since 2×8561985961² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 8561985896 and 8561985905.

It is not an unprimeable number, because it can be changed into a prime (8561980961) by changing a digit.

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 in 8 ways as a sum of consecutive naturals, for example, 1570306 + ... + 1575748.

Almost surely, 2^8561985961 is an apocalyptic number.

8561985961 is the 92531-st square number.

8561985961 is the 46266-th centered octagonal number.

It is an amenable number.

8561985961 is a deficient number, since it is larger than the sum of its proper divisors (534943790).

8561985961 is an frugal number, since it uses more digits than its factorization.

8561985961 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10920 (or 5460 counting only the distinct ones).

The product of its digits is 4665600, while the sum is 58.

The cubic root of 8561985961 is about 2045.7764290502.

The spelling of 8561985961 in words is "eight billion, five hundred sixty-one million, nine hundred eighty-five thousand, nine hundred sixty-one".