18214909621 has 2 divisors, whose sum is σ = 18214909622. Its totient is φ = 18214909620.

The previous prime is 18214909577. The next prime is 18214909663. The reversal of 18214909621 is 12690941281.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18164300625 + 50608996 = 134775^2 + 7114^2 .

It is a cyclic number.

It is not a de Polignac number, because 18214909621 - 2¹⁹ = 18214385333 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18214909021) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9107454810 + 9107454811.

It is an arithmetic number, because the mean of its divisors is an integer number (9107454811).

Almost surely, 2^18214909621 is an apocalyptic number.

It is an amenable number.

18214909621 is a deficient number, since it is larger than the sum of its proper divisors (1).

18214909621 is an equidigital number, since it uses as much as digits as its factorization.

18214909621 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 62208, while the sum is 43.

The spelling of 18214909621 in words is "eighteen billion, two hundred fourteen million, nine hundred nine thousand, six hundred twenty-one".