18783621 has 6 divisors (see below), whose sum is σ = 27131910. Its totient is φ = 12522408.

The previous prime is 18783607. The next prime is 18783641. The reversal of 18783621 is 12638781.

It can be written as a sum of positive squares in only one way, i.e., 9548100 + 9235521 = 3090^2 + 3039^2 .

It is not a de Polignac number, because 18783621 - 2⁹ = 18783109 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18783641) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1043526 + ... + 1043543.

It is an arithmetic number, because the mean of its divisors is an integer number (4521985).

Almost surely, 2^18783621 is an apocalyptic number.

It is an amenable number.

18783621 is a deficient number, since it is larger than the sum of its proper divisors (8348289).

18783621 is a wasteful number, since it uses less digits than its factorization.

18783621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2087075 (or 2087072 counting only the distinct ones).

The product of its digits is 16128, while the sum is 36.

The square root of 18783621 is about 4334.0074988398. The cubic root of 18783621 is about 265.8233370083.

The spelling of 18783621 in words is "eighteen million, seven hundred eighty-three thousand, six hundred twenty-one".