181999872 has 180 divisors, whose sum is σ = 554995056. Its totient is φ = 59304960.

The previous prime is 181999871. The next prime is 181999891. The reversal of 181999872 is 278999181.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is not an unprimeable number, because it can be changed into a prime (181999871) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 1389247 + ... + 1389377.

Almost surely, 2^181999872 is an apocalyptic number.

181999872 is a gapful number since it is divisible by the number (12) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 181999872, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (277497528).

181999872 is an abundant number, since it is smaller than the sum of its proper divisors (372995184).

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

181999872 is an equidigital number, since it uses as much as digits as its factorization.

181999872 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 226 (or 203 counting only the distinct ones).

The product of its digits is 653184, while the sum is 54.

The square root of 181999872 is about 13490.7328192356. The cubic root of 181999872 is about 566.7049779557.

The spelling of 181999872 in words is "one hundred eighty-one million, nine hundred ninety-nine thousand, eight hundred seventy-two".