18233730421 has 2 divisors, whose sum is σ = 18233730422. Its totient is φ = 18233730420.

The previous prime is 18233730353. The next prime is 18233730439. The reversal of 18233730421 is 12403733281.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17812906225 + 420824196 = 133465^2 + 20514^2 .

It is a cyclic number.

It is not a de Polignac number, because 18233730421 - 2¹⁹ = 18233206133 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18233730481) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9116865210 + 9116865211.

It is an arithmetic number, because the mean of its divisors is an integer number (9116865211).

Almost surely, 2^18233730421 is an apocalyptic number.

It is an amenable number.

18233730421 is a deficient number, since it is larger than the sum of its proper divisors (1).

18233730421 is an equidigital number, since it uses as much as digits as its factorization.

18233730421 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 24192, while the sum is 34.

The spelling of 18233730421 in words is "eighteen billion, two hundred thirty-three million, seven hundred thirty thousand, four hundred twenty-one".