161694145 has 4 divisors (see below), whose sum is σ = 194032980. Its totient is φ = 129355312.

The previous prime is 161694139. The next prime is 161694167. The reversal of 161694145 is 541496161.

161694145 = 8991² + 8992².

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 80856064 + 80838081 = 8992^2 + 8991^2 .

It is a cyclic number.

It is not a de Polignac number, because 161694145 - 2⁹ = 161693633 is a prime.

It is a super-2 number, since 2×161694145² = 52289993054562050, which contains 22 as substring.

It is an alternating number because its digits alternate between odd and even.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 16169410 + ... + 16169419.

It is an arithmetic number, because the mean of its divisors is an integer number (48508245).

Almost surely, 2^161694145 is an apocalyptic number.

161694145 is the 8992-nd centered square number.

It is an amenable number.

161694145 is a deficient number, since it is larger than the sum of its proper divisors (32338835).

161694145 is an equidigital number, since it uses as much as digits as its factorization.

161694145 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32338834.

The product of its digits is 25920, while the sum is 37.

The square root of 161694145 is about 12715.9012657381. The cubic root of 161694145 is about 544.7928904712.

The spelling of 161694145 in words is "one hundred sixty-one million, six hundred ninety-four thousand, one hundred forty-five".