18632160721 has 2 divisors, whose sum is σ = 18632160722. Its totient is φ = 18632160720.

The previous prime is 18632160713. The next prime is 18632160727. The reversal of 18632160721 is 12706123681.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12196110096 + 6436050625 = 110436^2 + 80225^2 .

It is an emirp because it is prime and its reverse (12706123681) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18632160721 - 2³ = 18632160713 is a prime.

It is not a weakly prime, because it can be changed into another prime (18632160727) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9316080360 + 9316080361.

It is an arithmetic number, because the mean of its divisors is an integer number (9316080361).

Almost surely, 2^18632160721 is an apocalyptic number.

It is an amenable number.

18632160721 is a deficient number, since it is larger than the sum of its proper divisors (1).

18632160721 is an equidigital number, since it uses as much as digits as its factorization.

18632160721 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 24192, while the sum is 37.

The spelling of 18632160721 in words is "eighteen billion, six hundred thirty-two million, one hundred sixty thousand, seven hundred twenty-one".