161751770230081 has 4 divisors (see below), whose sum is σ = 161755336152964. Its totient is φ = 161748204307200.

The previous prime is 161751770230073. The next prime is 161751770230093. The reversal of 161751770230081 is 180032077157161.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 49774210247056 + 111977559983025 = 7055084^2 + 10581945^2 .

It is a cyclic number.

It is not a de Polignac number, because 161751770230081 - 2³ = 161751770230073 is a prime.

It is a super-2 number, since 2×161751770230081² (a number of 29 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (161751770230781) 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, 1782893400 + ... + 1782984121.

It is an arithmetic number, because the mean of its divisors is an integer number (40438834038241).

Almost surely, 2^{161751770230081} is an apocalyptic number.

It is an amenable number.

161751770230081 is a deficient number, since it is larger than the sum of its proper divisors (3565922883).

161751770230081 is an equidigital number, since it uses as much as digits as its factorization.

161751770230081 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3565922882.

The product of its (nonzero) digits is 493920, while the sum is 49.

The spelling of 161751770230081 in words is "one hundred sixty-one trillion, seven hundred fifty-one billion, seven hundred seventy million, two hundred thirty thousand, eighty-one".