181868988 has 144 divisors (see below), whose sum is σ = 529105920. Its totient is φ = 48335616.

The previous prime is 181868987. The next prime is 181869001. The reversal of 181868988 is 889868181.

It is a super-2 number, since 2×181868988² = 66152657592288288, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (57).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (181868987) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 815445 + ... + 815667.

Almost surely, 2^181868988 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 181868988, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (264552960).

181868988 is an abundant number, since it is smaller than the sum of its proper divisors (347236932).

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

181868988 is a wasteful number, since it uses less digits than its factorization.

181868988 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 336 (or 327 counting only the distinct ones).

The product of its digits is 1769472, while the sum is 57.

The square root of 181868988 is about 13485.8810613174. The cubic root of 181868988 is about 566.5690980036.

The spelling of 181868988 in words is "one hundred eighty-one million, eight hundred sixty-eight thousand, nine hundred eighty-eight".