181689323840 has 28 divisors (see below), whose sum is σ = 432647703156. Its totient is φ = 72675729408.

The previous prime is 181689323759. The next prime is 181689323857. The reversal of 181689323840 is 48323986181.

It can be written as a sum of positive squares in 2 ways, for example, as 80606023744 + 101083300096 = 283912^2 + 317936^2 .

It is a super-2 number, since 2×181689323840² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 283889249 + ... + 283889888.

Almost surely, 2^181689323840 is an apocalyptic number.

181689323840 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

181689323840 is an abundant number, since it is smaller than the sum of its proper divisors (250958379316).

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

181689323840 is an equidigital number, since it uses as much as digits as its factorization.

181689323840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 567779154 (or 567779144 counting only the distinct ones).

The product of its (nonzero) digits is 1990656, while the sum is 53.

The spelling of 181689323840 in words is "one hundred eighty-one billion, six hundred eighty-nine million, three hundred twenty-three thousand, eight hundred forty".