161680445 has 4 divisors (see below), whose sum is σ = 194016540. Its totient is φ = 129344352.

The previous prime is 161680427. The next prime is 161680457. The reversal of 161680445 is 544086161.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 107599129 + 54081316 = 10373^2 + 7354^2 .

It is a cyclic number.

It is not a de Polignac number, because 161680445 - 2¹⁰ = 161679421 is a prime.

It is a super-2 number, since 2×161680445² = 52281132590796050, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 16168040 + ... + 16168049.

It is an arithmetic number, because the mean of its divisors is an integer number (48504135).

Almost surely, 2^161680445 is an apocalyptic number.

It is an amenable number.

161680445 is a deficient number, since it is larger than the sum of its proper divisors (32336095).

161680445 is an equidigital number, since it uses as much as digits as its factorization.

161680445 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32336094.

The product of its (nonzero) digits is 23040, while the sum is 35.

The square root of 161680445 is about 12715.3625587319. The cubic root of 161680445 is about 544.7775036568. Note that the first 3 decimals are identical.

The spelling of 161680445 in words is "one hundred sixty-one million, six hundred eighty thousand, four hundred forty-five".