161798401 has 8 divisors (see below), whose sum is σ = 172889640. Its totient is φ = 150882048.

The previous prime is 161798359. The next prime is 161798407. The reversal of 161798401 is 104897161.

It is a Cunningham number, because it is equal to 12720²+1.

It can be written as a sum of positive squares in 4 ways, for example, as 36917776 + 124880625 = 6076^2 + 11175^2 .

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 161798401 - 2¹⁷ = 161667329 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (161798407) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 41806 + ... + 45511.

It is an arithmetic number, because the mean of its divisors is an integer number (21611205).

Almost surely, 2^161798401 is an apocalyptic number.

It is an amenable number.

161798401 is a deficient number, since it is larger than the sum of its proper divisors (11091239).

161798401 is a wasteful number, since it uses less digits than its factorization.

161798401 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 87443.

The product of its (nonzero) digits is 12096, while the sum is 37.

The square root of 161798401 is about 12720.0000393082. Note that the first 4 decimals coincide. The cubic root of 161798401 is about 544.9099545424.

The spelling of 161798401 in words is "one hundred sixty-one million, seven hundred ninety-eight thousand, four hundred one".