18912961493 has 2 divisors, whose sum is σ = 18912961494. Its totient is φ = 18912961492.

The previous prime is 18912961481. The next prime is 18912961541. The reversal of 18912961493 is 39416921981.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18762972484 + 149989009 = 136978^2 + 12247^2 .

It is a cyclic number.

It is not a de Polignac number, because 18912961493 - 2²⁴ = 18896184277 is a prime.

It is a super-2 number, since 2×18912961493² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18912961453) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9456480746 + 9456480747.

It is an arithmetic number, because the mean of its divisors is an integer number (9456480747).

Almost surely, 2^18912961493 is an apocalyptic number.

It is an amenable number.

18912961493 is a deficient number, since it is larger than the sum of its proper divisors (1).

18912961493 is an equidigital number, since it uses as much as digits as its factorization.

18912961493 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 839808, while the sum is 53.

The spelling of 18912961493 in words is "eighteen billion, nine hundred twelve million, nine hundred sixty-one thousand, four hundred ninety-three".