181638023 has 4 divisors (see below), whose sum is σ = 207586320. Its totient is φ = 155689728.

The previous prime is 181638007. The next prime is 181638031. The reversal of 181638023 is 320836181.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 181638023 - 2⁴ = 181638007 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (181634023) 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, 12974138 + ... + 12974151.

It is an arithmetic number, because the mean of its divisors is an integer number (51896580).

Almost surely, 2^181638023 is an apocalyptic number.

181638023 is a deficient number, since it is larger than the sum of its proper divisors (25948297).

181638023 is an equidigital number, since it uses as much as digits as its factorization.

181638023 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25948296.

The product of its (nonzero) digits is 6912, while the sum is 32.

The square root of 181638023 is about 13477.3151257956. The cubic root of 181638023 is about 566.3291577649.

The spelling of 181638023 in words is "one hundred eighty-one million, six hundred thirty-eight thousand, twenty-three".