7720961161 has 3 divisors (see below), whose sum is σ = 7721049031. Its totient is φ = 7720873292.

The previous prime is 7720961159. The next prime is 7720961167. The reversal of 7720961161 is 1611690277.

The square root of 7720961161 is 87869.

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

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 1611690277 = 73 ⋅22077949.

It can be written as a sum of positive squares in only one way, i.e., 321520761 + 7399440400 = 17931^2 + 86020^2 .

It is not a de Polignac number, because 7720961161 - 2¹ = 7720961159 is a prime.

It is a super-2 number, since 2×7720961161² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (7720961167) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 43935 + ... + 131803.

Almost surely, 2^7720961161 is an apocalyptic number.

7720961161 is the 87869-th square number.

7720961161 is the 43935-th centered octagonal number.

It is an amenable number.

7720961161 is a deficient number, since it is larger than the sum of its proper divisors (87870).

7720961161 is an frugal number, since it uses more digits than its factorization.

7720961161 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 175738 (or 87869 counting only the distinct ones).

The product of its (nonzero) digits is 31752, while the sum is 40.

The cubic root of 7720961161 is about 1976.4710430003.

The spelling of 7720961161 in words is "seven billion, seven hundred twenty million, nine hundred sixty-one thousand, one hundred sixty-one".