18989471 has 2 divisors, whose sum is σ = 18989472. Its totient is φ = 18989470.

The previous prime is 18989441. The next prime is 18989479. The reversal of 18989471 is 17498981.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18989471 is a prime.

It is a super-3 number, since 3×18989471³ (a number of 23 digits) contains 333 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18989479) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9494735 + 9494736.

It is an arithmetic number, because the mean of its divisors is an integer number (9494736).

Almost surely, 2^18989471 is an apocalyptic number.

18989471 is a deficient number, since it is larger than the sum of its proper divisors (1).

18989471 is an equidigital number, since it uses as much as digits as its factorization.

18989471 is an evil number, because the sum of its binary digits is even.

The product of its digits is 145152, while the sum is 47.

The square root of 18989471 is about 4357.6910170410. The cubic root of 18989471 is about 266.7908652365.

The spelling of 18989471 in words is "eighteen million, nine hundred eighty-nine thousand, four hundred seventy-one".