161345687321 has 60 divisors (see below), whose sum is σ = 209943348480. Its totient is φ = 123506903520.

The previous prime is 161345687317. The next prime is 161345687323. The reversal of 161345687321 is 123786543161.

It is not a de Polignac number, because 161345687321 - 2² = 161345687317 is a prime.

It is not an unprimeable number, because it can be changed into a prime (161345687323) by changing a digit.

It is a polite number, since it can be written in 59 ways as a sum of consecutive naturals, for example, 43382300 + ... + 43386018.

It is an arithmetic number, because the mean of its divisors is an integer number (3499055808).

Almost surely, 2^161345687321 is an apocalyptic number.

It is an amenable number.

161345687321 is a deficient number, since it is larger than the sum of its proper divisors (48597661159).

161345687321 is an frugal number, since it uses more digits than its factorization.

161345687321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3816 (or 3770 counting only the distinct ones).

The product of its digits is 725760, while the sum is 47.

The spelling of 161345687321 in words is "one hundred sixty-one billion, three hundred forty-five million, six hundred eighty-seven thousand, three hundred twenty-one".