18864971 has 2 divisors, whose sum is σ = 18864972. Its totient is φ = 18864970.

The previous prime is 18864959. The next prime is 18864973. The reversal of 18864971 is 17946881.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18864971 is a prime.

It is a Sophie Germain prime.

Together with 18864973, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (18864973) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9432485 + 9432486.

It is an arithmetic number, because the mean of its divisors is an integer number (9432486).

Almost surely, 2^18864971 is an apocalyptic number.

18864971 is a deficient number, since it is larger than the sum of its proper divisors (1).

18864971 is an equidigital number, since it uses as much as digits as its factorization.

18864971 is an evil number, because the sum of its binary digits is even.

The product of its digits is 96768, while the sum is 44.

The square root of 18864971 is about 4343.3824376861. The cubic root of 18864971 is about 266.2065358455.

The spelling of 18864971 in words is "eighteen million, eight hundred sixty-four thousand, nine hundred seventy-one".