18350921 has 2 divisors, whose sum is σ = 18350922. Its totient is φ = 18350920.

The previous prime is 18350909. The next prime is 18350951. The reversal of 18350921 is 12905381.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17977600 + 373321 = 4240^2 + 611^2 .

It is an emirp because it is prime and its reverse (12905381) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18350921 - 2¹⁰ = 18349897 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (18350951) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9175460 + 9175461.

It is an arithmetic number, because the mean of its divisors is an integer number (9175461).

Almost surely, 2^18350921 is an apocalyptic number.

It is an amenable number.

18350921 is a deficient number, since it is larger than the sum of its proper divisors (1).

18350921 is an equidigital number, since it uses as much as digits as its factorization.

18350921 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2160, while the sum is 29.

The square root of 18350921 is about 4283.7974975482. The cubic root of 18350921 is about 263.7662886102.

The spelling of 18350921 in words is "eighteen million, three hundred fifty thousand, nine hundred twenty-one".