161822105257 has 4 divisors (see below), whose sum is σ = 164875352580. Its totient is φ = 158768857936.

The previous prime is 161822105231. The next prime is 161822105279. The reversal of 161822105257 is 752501228161.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 752501228161 = 15607 ⋅48215623.

It can be written as a sum of positive squares in 2 ways, for example, as 55804140441 + 106017964816 = 236229^2 + 325604^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-161822105257 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (161822105227) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1526623582 + ... + 1526623687.

It is an arithmetic number, because the mean of its divisors is an integer number (41218838145).

Almost surely, 2^161822105257 is an apocalyptic number.

It is an amenable number.

161822105257 is a deficient number, since it is larger than the sum of its proper divisors (3053247323).

161822105257 is an equidigital number, since it uses as much as digits as its factorization.

161822105257 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3053247322.

The product of its (nonzero) digits is 67200, while the sum is 40.

The spelling of 161822105257 in words is "one hundred sixty-one billion, eight hundred twenty-two million, one hundred five thousand, two hundred fifty-seven".