161612281 has 2 divisors, whose sum is σ = 161612282. Its totient is φ = 161612280.

The previous prime is 161612279. The next prime is 161612303. The reversal of 161612281 is 182216161.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 140635881 + 20976400 = 11859^2 + 4580^2 .

It is a cyclic number.

It is not a de Polignac number, because 161612281 - 2¹ = 161612279 is a prime.

It is a super-2 number, since 2×161612281² = 52237058740045922, which contains 22 as substring.

Together with 161612279, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (161612681) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80806140 + 80806141.

It is an arithmetic number, because the mean of its divisors is an integer number (80806141).

Almost surely, 2^161612281 is an apocalyptic number.

It is an amenable number.

161612281 is a deficient number, since it is larger than the sum of its proper divisors (1).

161612281 is an equidigital number, since it uses as much as digits as its factorization.

161612281 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1152, while the sum is 28.

The square root of 161612281 is about 12712.6818964371. The cubic root of 161612281 is about 544.7009340309.

The spelling of 161612281 in words is "one hundred sixty-one million, six hundred twelve thousand, two hundred eighty-one".