168991788 has 144 divisors (see below), whose sum is σ = 483753984. Its totient is φ = 45722880.

The previous prime is 168991727. The next prime is 168991789. The reversal of 168991788 is 887199861.

It is a super-2 number, since 2×168991788² = 57116448822873888, which contains 22 as substring.

Its product of digits (1741824) is a multiple of the sum of its prime divisors (243).

It is not an unprimeable number, because it can be changed into a prime (168991789) 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 47 ways as a sum of consecutive naturals, for example, 1330581 + ... + 1330707.

Almost surely, 2^168991788 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 168991788, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (241876992).

168991788 is an abundant number, since it is smaller than the sum of its proper divisors (314762196).

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

168991788 is a wasteful number, since it uses less digits than its factorization.

168991788 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 252 (or 243 counting only the distinct ones).

The product of its digits is 1741824, while the sum is 57.

The square root of 168991788 is about 12999.6841500092. The cubic root of 168991788 is about 552.8685261343.

The spelling of 168991788 in words is "one hundred sixty-eight million, nine hundred ninety-one thousand, seven hundred eighty-eight".