18783421 has 2 divisors, whose sum is σ = 18783422. Its totient is φ = 18783420.

The previous prime is 18783407. The next prime is 18783437. The reversal of 18783421 is 12438781.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16695396 + 2088025 = 4086^2 + 1445^2 .

It is a cyclic number.

It is not a de Polignac number, because 18783421 - 2⁷ = 18783293 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18783461) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9391710 + 9391711.

It is an arithmetic number, because the mean of its divisors is an integer number (9391711).

Almost surely, 2^18783421 is an apocalyptic number.

It is an amenable number.

18783421 is a deficient number, since it is larger than the sum of its proper divisors (1).

18783421 is an equidigital number, since it uses as much as digits as its factorization.

18783421 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 10752, while the sum is 34.

The square root of 18783421 is about 4333.9844254450. The cubic root of 18783421 is about 265.8223935471.

The spelling of 18783421 in words is "eighteen million, seven hundred eighty-three thousand, four hundred twenty-one".