17987987 has 2 divisors, whose sum is σ = 17987988. Its totient is φ = 17987986.

The previous prime is 17987951. The next prime is 17987993. The reversal of 17987987 is 78978971.

It is a strong prime.

It is an emirp because it is prime and its reverse (78978971) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 17987987 - 2¹⁰ = 17986963 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (17987947) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8993993 + 8993994.

It is an arithmetic number, because the mean of its divisors is an integer number (8993994).

Almost surely, 2^17987987 is an apocalyptic number.

17987987 is a deficient number, since it is larger than the sum of its proper divisors (1).

17987987 is an equidigital number, since it uses as much as digits as its factorization.

17987987 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1778112, while the sum is 56.

The square root of 17987987 is about 4241.2247052001. The cubic root of 17987987 is about 262.0158246565.

The spelling of 17987987 in words is "seventeen million, nine hundred eighty-seven thousand, nine hundred eighty-seven".