161777710657 has 8 divisors (see below), whose sum is σ = 171311735592. Its totient is φ = 152245651200.

The previous prime is 161777710643. The next prime is 161777710751. The reversal of 161777710657 is 756017777161.

It is a Cunningham number, because it is equal to 402216²+1.

It can be written as a sum of positive squares in 4 ways, for example, as 69676993296 + 92100717361 = 263964^2 + 303481^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 161777710657 - 2²³ = 161769322049 is a prime.

It is a super-2 number, since 2×161777710657² (a number of 23 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 = 161777710598 and 161777710607.

It is not an unprimeable number, because it can be changed into a prime (161777710957) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 320194 + ... + 652747.

It is an arithmetic number, because the mean of its divisors is an integer number (21413966949).

Almost surely, 2^161777710657 is an apocalyptic number.

161777710657 is a gapful number since it is divisible by the number (17) formed by its first and last digit.

It is an amenable number.

161777710657 is a deficient number, since it is larger than the sum of its proper divisors (9534024935).

161777710657 is an equidigital number, since it uses as much as digits as its factorization.

161777710657 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 982739.

The product of its (nonzero) digits is 3025260, while the sum is 55.

The spelling of 161777710657 in words is "one hundred sixty-one billion, seven hundred seventy-seven million, seven hundred ten thousand, six hundred fifty-seven".