18029621 has 2 divisors, whose sum is σ = 18029622. Its totient is φ = 18029620.

The previous prime is 18029579. The next prime is 18029629. The reversal of 18029621 is 12692081.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16313521 + 1716100 = 4039^2 + 1310^2 .

It is a cyclic number.

It is not a de Polignac number, because 18029621 - 2¹⁰ = 18028597 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18029629) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9014810 + 9014811.

It is an arithmetic number, because the mean of its divisors is an integer number (9014811).

Almost surely, 2^18029621 is an apocalyptic number.

It is an amenable number.

18029621 is a deficient number, since it is larger than the sum of its proper divisors (1).

18029621 is an equidigital number, since it uses as much as digits as its factorization.

18029621 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1728, while the sum is 29.

The square root of 18029621 is about 4246.1301204744. The cubic root of 18029621 is about 262.2178180086.

The spelling of 18029621 in words is "eighteen million, twenty-nine thousand, six hundred twenty-one".