18302040721 has 2 divisors, whose sum is σ = 18302040722. Its totient is φ = 18302040720.

The previous prime is 18302040709. The next prime is 18302040749. The reversal of 18302040721 is 12704020381.

It is an a-pointer prime, because the next prime (18302040749) can be obtained adding 18302040721 to its sum of digits (28).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18188298496 + 113742225 = 134864^2 + 10665^2 .

It is a cyclic number.

It is not a de Polignac number, because 18302040721 - 2⁵ = 18302040689 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 18302040721.

It is not a weakly prime, because it can be changed into another prime (18302047721) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9151020360 + 9151020361.

It is an arithmetic number, because the mean of its divisors is an integer number (9151020361).

Almost surely, 2^18302040721 is an apocalyptic number.

It is an amenable number.

18302040721 is a deficient number, since it is larger than the sum of its proper divisors (1).

18302040721 is an equidigital number, since it uses as much as digits as its factorization.

18302040721 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2688, while the sum is 28.

The spelling of 18302040721 in words is "eighteen billion, three hundred two million, forty thousand, seven hundred twenty-one".