161668542 has 48 divisors (see below), whose sum is σ = 380071440. Its totient is φ = 45706752.

The previous prime is 161668517. The next prime is 161668553. The reversal of 161668542 is 245866161.

It is a happy number.

It is a super-2 number, since 2×161668542² = 52273434944811528, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 161668542.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 25684 + ... + 31352.

It is an arithmetic number, because the mean of its divisors is an integer number (7918155).

Almost surely, 2^161668542 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 161668542, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (190035720).

161668542 is an abundant number, since it is smaller than the sum of its proper divisors (218402898).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

161668542 is a wasteful number, since it uses less digits than its factorization.

161668542 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5785 (or 5778 counting only the distinct ones).

The product of its digits is 69120, while the sum is 39.

The square root of 161668542 is about 12714.8944942536. The cubic root of 161668542 is about 544.7641343926.

The spelling of 161668542 in words is "one hundred sixty-one million, six hundred sixty-eight thousand, five hundred forty-two".