181563640 has 16 divisors (see below), whose sum is σ = 408518280. Its totient is φ = 72625440.

The previous prime is 181563623. The next prime is 181563643. The reversal of 181563640 is 46365181.

It is a happy number.

181563640 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a junction number, because it is equal to n+sod(n) for n = 181563596 and 181563605.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (181563643) 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, 2269506 + ... + 2269585.

Almost surely, 2^181563640 is an apocalyptic number.

181563640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

181563640 is an abundant number, since it is smaller than the sum of its proper divisors (226954640).

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

181563640 is a wasteful number, since it uses less digits than its factorization.

181563640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4539102 (or 4539098 counting only the distinct ones).

The product of its (nonzero) digits is 17280, while the sum is 34.

The square root of 181563640 is about 13474.5552802310. Note that the first 3 decimals coincide. The cubic root of 181563640 is about 566.2518409627.

The spelling of 181563640 in words is "one hundred eighty-one million, five hundred sixty-three thousand, six hundred forty".