77217850161 has 9 divisors (see below), whose sum is σ = 111538098841. Its totient is φ = 51478011012.

The previous prime is 77217850147. The next prime is 77217850169. The reversal of 77217850161 is 16105871277.

The square root of 77217850161 is 277881.

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

77217850161 is a `hidden beast` number, since 7 + 72 + 1 + 78 + 501 + 6 + 1 = 666.

It is a tau number, because it is divible by the number of its divisors (9).

It is not a de Polignac number, because 77217850161 - 2¹⁹ = 77217325873 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (77217850169) 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, 787330 + ... + 879956.

Almost surely, 2^77217850161 is an apocalyptic number.

77217850161 is the 277881-st square number.

77217850161 is the 138941-st centered octagonal number.

It is an amenable number.

77217850161 is a deficient number, since it is larger than the sum of its proper divisors (34320248680).

77217850161 is an frugal number, since it uses more digits than its factorization.

77217850161 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 185260 (or 92630 counting only the distinct ones).

The product of its (nonzero) digits is 164640, while the sum is 45.

The spelling of 77217850161 in words is "seventy-seven billion, two hundred seventeen million, eight hundred fifty thousand, one hundred sixty-one".