18645971 has 2 divisors, whose sum is σ = 18645972. Its totient is φ = 18645970.

The previous prime is 18645967. The next prime is 18646003. The reversal of 18645971 is 17954681.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 18645971 - 2² = 18645967 is a prime.

It is not a weakly prime, because it can be changed into another prime (18645941) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9322985 + 9322986.

It is an arithmetic number, because the mean of its divisors is an integer number (9322986).

Almost surely, 2^18645971 is an apocalyptic number.

18645971 is a deficient number, since it is larger than the sum of its proper divisors (1).

18645971 is an equidigital number, since it uses as much as digits as its factorization.

18645971 is an evil number, because the sum of its binary digits is even.

The product of its digits is 60480, while the sum is 41.

The square root of 18645971 is about 4318.0980767000. The cubic root of 18645971 is about 265.1724094624.

The spelling of 18645971 in words is "eighteen million, six hundred forty-five thousand, nine hundred seventy-one".