18272821 has 8 divisors (see below), whose sum is σ = 20913984. Its totient is φ = 15639360.

The previous prime is 18272809. The next prime is 18272867. The reversal of 18272821 is 12827281.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 18272821 - 2⁷ = 18272693 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18272021) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4686 + ... + 7648.

It is an arithmetic number, because the mean of its divisors is an integer number (2614248).

Almost surely, 2^18272821 is an apocalyptic number.

It is an amenable number.

18272821 is a deficient number, since it is larger than the sum of its proper divisors (2641163).

18272821 is an equidigital number, since it uses as much as digits as its factorization.

18272821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3851.

The product of its digits is 3584, while the sum is 31.

The square root of 18272821 is about 4274.6720342033. The cubic root of 18272821 is about 263.3915673522.

The spelling of 18272821 in words is "eighteen million, two hundred seventy-two thousand, eight hundred twenty-one".