161621734706 has 4 divisors (see below), whose sum is σ = 242432602062. Its totient is φ = 80810867352.

The previous prime is 161621734663. The next prime is 161621734753. The reversal of 161621734706 is 607437126161.

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

It can be written as a sum of positive squares in only one way, i.e., 139308844081 + 22312890625 = 373241^2 + 149375^2 .

It is a super-2 number, since 2×161621734706² (a number of 23 digits) contains 22 as substring.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40405433675 + ... + 40405433678.

Almost surely, 2^161621734706 is an apocalyptic number.

161621734706 is a deficient number, since it is larger than the sum of its proper divisors (80810867356).

161621734706 is an equidigital number, since it uses as much as digits as its factorization.

161621734706 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 80810867355.

The product of its (nonzero) digits is 254016, while the sum is 44.

The spelling of 161621734706 in words is "one hundred sixty-one billion, six hundred twenty-one million, seven hundred thirty-four thousand, seven hundred six".