161721566201 has 8 divisors (see below), whose sum is σ = 183328091520. Its totient is φ = 141424527312.

The previous prime is 161721566197. The next prime is 161721566221. The reversal of 161721566201 is 102665127161.

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 161721566201 - 2² = 161721566197 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 (161721566221) 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, 327371345 + ... + 327371838.

It is an arithmetic number, because the mean of its divisors is an integer number (22916011440).

Almost surely, 2^161721566201 is an apocalyptic number.

It is an amenable number.

161721566201 is a deficient number, since it is larger than the sum of its proper divisors (21606525319).

161721566201 is a wasteful number, since it uses less digits than its factorization.

161721566201 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 654743215.

The product of its (nonzero) digits is 30240, while the sum is 38.

The spelling of 161721566201 in words is "one hundred sixty-one billion, seven hundred twenty-one million, five hundred sixty-six thousand, two hundred one".