18545221493 has 2 divisors, whose sum is σ = 18545221494. Its totient is φ = 18545221492.

The previous prime is 18545221469. The next prime is 18545221501. The reversal of 18545221493 is 39412254581.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11679773329 + 6865448164 = 108073^2 + 82858^2 .

It is a cyclic number.

It is not a de Polignac number, because 18545221493 - 2⁸ = 18545221237 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18545221423) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9272610746 + 9272610747.

It is an arithmetic number, because the mean of its divisors is an integer number (9272610747).

Almost surely, 2^18545221493 is an apocalyptic number.

It is an amenable number.

18545221493 is a deficient number, since it is larger than the sum of its proper divisors (1).

18545221493 is an equidigital number, since it uses as much as digits as its factorization.

18545221493 is an evil number, because the sum of its binary digits is even.

The product of its digits is 345600, while the sum is 44.

The spelling of 18545221493 in words is "eighteen billion, five hundred forty-five million, two hundred twenty-one thousand, four hundred ninety-three".