660776161 has 4 divisors (see below), whose sum is σ = 660865024. Its totient is φ = 660687300.

The previous prime is 660776159. The next prime is 660776261. The reversal of 660776161 is 161677066.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 161677066 = 2 ⋅80838533.

It is a cyclic number.

It is not a de Polignac number, because 660776161 - 2¹ = 660776159 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (660776261) 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, 32145 + ... + 48526.

It is an arithmetic number, because the mean of its divisors is an integer number (165216256).

Almost surely, 2^660776161 is an apocalyptic number.

It is an amenable number.

660776161 is a deficient number, since it is larger than the sum of its proper divisors (88863).

660776161 is an equidigital number, since it uses as much as digits as its factorization.

660776161 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 88862.

The product of its (nonzero) digits is 63504, while the sum is 40.

The square root of 660776161 is about 25705.5667317412. The cubic root of 660776161 is about 870.9999340927. Note that the first 4 decimals are identical.

The spelling of 660776161 in words is "six hundred sixty million, seven hundred seventy-six thousand, one hundred sixty-one".