17987993 has 2 divisors, whose sum is σ = 17987994. Its totient is φ = 17987992.

The previous prime is 17987987. The next prime is 17988007. The reversal of 17987993 is 39978971.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17081689 + 906304 = 4133^2 + 952^2 .

It is a cyclic number.

It is not a de Polignac number, because 17987993 - 2¹⁴ = 17971609 is a prime.

It is a plaindrome in base 16.

It is not a weakly prime, because it can be changed into another prime (17987903) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8993996 + 8993997.

It is an arithmetic number, because the mean of its divisors is an integer number (8993997).

Almost surely, 2^17987993 is an apocalyptic number.

It is an amenable number.

17987993 is a deficient number, since it is larger than the sum of its proper divisors (1).

17987993 is an equidigital number, since it uses as much as digits as its factorization.

17987993 is an evil number, because the sum of its binary digits is even.

The product of its digits is 857304, while the sum is 53.

The square root of 17987993 is about 4241.2254125429. The cubic root of 17987993 is about 262.0158537888.

The spelling of 17987993 in words is "seventeen million, nine hundred eighty-seven thousand, nine hundred ninety-three".