18441278993 has 2 divisors, whose sum is σ = 18441278994. Its totient is φ = 18441278992.

The previous prime is 18441278963. The next prime is 18441279001. The reversal of 18441278993 is 39987214481.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14610040384 + 3831238609 = 120872^2 + 61897^2 .

It is an emirp because it is prime and its reverse (39987214481) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18441278993 - 2¹⁶ = 18441213457 is a prime.

It is not a weakly prime, because it can be changed into another prime (18441278953) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9220639496 + 9220639497.

It is an arithmetic number, because the mean of its divisors is an integer number (9220639497).

Almost surely, 2^18441278993 is an apocalyptic number.

It is an amenable number.

18441278993 is a deficient number, since it is larger than the sum of its proper divisors (1).

18441278993 is an equidigital number, since it uses as much as digits as its factorization.

18441278993 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3483648, while the sum is 56.

The spelling of 18441278993 in words is "eighteen billion, four hundred forty-one million, two hundred seventy-eight thousand, nine hundred ninety-three".