18640921423 has 2 divisors, whose sum is σ = 18640921424. Its totient is φ = 18640921422.

The previous prime is 18640921417. The next prime is 18640921469. The reversal of 18640921423 is 32412904681.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 18640921423 - 2⁵ = 18640921391 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18640921723) 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, 9320460711 + 9320460712.

It is an arithmetic number, because the mean of its divisors is an integer number (9320460712).

Almost surely, 2^18640921423 is an apocalyptic number.

18640921423 is a deficient number, since it is larger than the sum of its proper divisors (1).

18640921423 is an equidigital number, since it uses as much as digits as its factorization.

18640921423 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 82944, while the sum is 40.

It can be divided in two parts, 186 and 40921423, that added together give a square (40921609 = 6397²).

The spelling of 18640921423 in words is "eighteen billion, six hundred forty million, nine hundred twenty-one thousand, four hundred twenty-three".