161321797331 has 2 divisors, whose sum is σ = 161321797332. Its totient is φ = 161321797330.

The previous prime is 161321797319. The next prime is 161321797387. The reversal of 161321797331 is 133797123161.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 161321797331 - 2⁶ = 161321797267 is a prime.

It is a super-2 number, since 2×161321797331² (a number of 23 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (161321797391) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80660898665 + 80660898666.

It is an arithmetic number, because the mean of its divisors is an integer number (80660898666).

Almost surely, 2^161321797331 is an apocalyptic number.

161321797331 is a deficient number, since it is larger than the sum of its proper divisors (1).

161321797331 is an equidigital number, since it uses as much as digits as its factorization.

161321797331 is an evil number, because the sum of its binary digits is even.

The product of its digits is 142884, while the sum is 44.

The spelling of 161321797331 in words is "one hundred sixty-one billion, three hundred twenty-one million, seven hundred ninety-seven thousand, three hundred thirty-one".