180021640 has 16 divisors (see below), whose sum is σ = 405048780. Its totient is φ = 72008640.

The previous prime is 180021623. The next prime is 180021643. The reversal of 180021640 is 46120081.

180021640 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 166048996 + 13972644 = 12886^2 + 3738^2 .

It is not an unprimeable number, because it can be changed into a prime (180021643) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2250231 + ... + 2250310.

Almost surely, 2^180021640 is an apocalyptic number.

180021640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

180021640 is an abundant number, since it is smaller than the sum of its proper divisors (225027140).

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

180021640 is a wasteful number, since it uses less digits than its factorization.

180021640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4500552 (or 4500548 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 22.

The square root of 180021640 is about 13417.2143159450. The cubic root of 180021640 is about 564.6442431105.

The spelling of 180021640 in words is "one hundred eighty million, twenty-one thousand, six hundred forty".