18617947 has 2 divisors, whose sum is σ = 18617948. Its totient is φ = 18617946.

The previous prime is 18617939. The next prime is 18617957. The reversal of 18617947 is 74971681.

It is a weak prime.

It is an emirp because it is prime and its reverse (74971681) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18617947 - 2³ = 18617939 is a prime.

It is not a weakly prime, because it can be changed into another prime (18617957) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9308973 + 9308974.

It is an arithmetic number, because the mean of its divisors is an integer number (9308974).

Almost surely, 2^18617947 is an apocalyptic number.

18617947 is a deficient number, since it is larger than the sum of its proper divisors (1).

18617947 is an equidigital number, since it uses as much as digits as its factorization.

18617947 is an evil number, because the sum of its binary digits is even.

The product of its digits is 84672, while the sum is 43.

The square root of 18617947 is about 4314.8519093939. The cubic root of 18617947 is about 265.0394957152.

The spelling of 18617947 in words is "eighteen million, six hundred seventeen thousand, nine hundred forty-seven".