18607993 has 2 divisors, whose sum is σ = 18607994. Its totient is φ = 18607992.

The previous prime is 18607991. The next prime is 18608017. The reversal of 18607993 is 39970681.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12981609 + 5626384 = 3603^2 + 2372^2 .

It is an emirp because it is prime and its reverse (39970681) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18607993 - 2¹ = 18607991 is a prime.

Together with 18607991, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (18607991) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9303996 + 9303997.

It is an arithmetic number, because the mean of its divisors is an integer number (9303997).

Almost surely, 2^18607993 is an apocalyptic number.

It is an amenable number.

18607993 is a deficient number, since it is larger than the sum of its proper divisors (1).

18607993 is an equidigital number, since it uses as much as digits as its factorization.

18607993 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 81648, while the sum is 43.

The square root of 18607993 is about 4313.6982972851. The cubic root of 18607993 is about 264.9922532445.

It can be divided in two parts, 18607 and 993, that added together give a square (19600 = 140²).

The spelling of 18607993 in words is "eighteen million, six hundred seven thousand, nine hundred ninety-three".