18661271 has 2 divisors, whose sum is σ = 18661272. Its totient is φ = 18661270.

The previous prime is 18661259. The next prime is 18661277. The reversal of 18661271 is 17216681.

It is a happy number.

It is a strong prime.

It is an emirp because it is prime and its reverse (17216681) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18661271 - 2¹⁸ = 18399127 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18661277) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9330635 + 9330636.

It is an arithmetic number, because the mean of its divisors is an integer number (9330636).

Almost surely, 2^18661271 is an apocalyptic number.

18661271 is a deficient number, since it is larger than the sum of its proper divisors (1).

18661271 is an equidigital number, since it uses as much as digits as its factorization.

18661271 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4032, while the sum is 32.

The square root of 18661271 is about 4319.8693267274. The cubic root of 18661271 is about 265.2449189368.

The spelling of 18661271 in words is "eighteen million, six hundred sixty-one thousand, two hundred seventy-one".