161778083697 has 6 divisors (see below), whose sum is σ = 233679454242. Its totient is φ = 107852055792.

The previous prime is 161778083693. The next prime is 161778083707. The reversal of 161778083697 is 796380877161.

161778083697 is a `hidden beast` number, since 1 + 617 + 7 + 8 + 0 + 8 + 3 + 6 + 9 + 7 = 666.

It can be written as a sum of positive squares in only one way, i.e., 95466168576 + 66311915121 = 308976^2 + 257511^2 .

It is not a de Polignac number, because 161778083697 - 2² = 161778083693 is a prime.

It is not an unprimeable number, because it can be changed into a prime (161778083693) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 8987671308 + ... + 8987671325.

It is an arithmetic number, because the mean of its divisors is an integer number (38946575707).

Almost surely, 2^161778083697 is an apocalyptic number.

It is an amenable number.

161778083697 is a deficient number, since it is larger than the sum of its proper divisors (71901370545).

161778083697 is a wasteful number, since it uses less digits than its factorization.

161778083697 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17975342639 (or 17975342636 counting only the distinct ones).

The product of its (nonzero) digits is 21337344, while the sum is 63.

The spelling of 161778083697 in words is "one hundred sixty-one billion, seven hundred seventy-eight million, eighty-three thousand, six hundred ninety-seven".