161320311021 has 8 divisors (see below), whose sum is σ = 219670210944. Its totient is φ = 105258642560.

The previous prime is 161320311017. The next prime is 161320311029. The reversal of 161320311021 is 120113023161.

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 161320311021 - 2² = 161320311017 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161320311029) 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, 572057700 + ... + 572057981.

It is an arithmetic number, because the mean of its divisors is an integer number (27458776368).

Almost surely, 2^161320311021 is an apocalyptic number.

It is an amenable number.

161320311021 is a deficient number, since it is larger than the sum of its proper divisors (58349899923).

161320311021 is a wasteful number, since it uses less digits than its factorization.

161320311021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1144115731.

The product of its (nonzero) digits is 216, while the sum is 21.

Adding to 161320311021 its reverse (120113023161), we get a palindrome (281433334182).

The spelling of 161320311021 in words is "one hundred sixty-one billion, three hundred twenty million, three hundred eleven thousand, twenty-one".