20181247 has 2 divisors, whose sum is σ = 20181248. Its totient is φ = 20181246.

The previous prime is 20181229. The next prime is 20181311. The reversal of 20181247 is 74218102.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20181247 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20181047) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10090623 + 10090624.

It is an arithmetic number, because the mean of its divisors is an integer number (10090624).

Almost surely, 2^20181247 is an apocalyptic number.

20181247 is a deficient number, since it is larger than the sum of its proper divisors (1).

20181247 is an equidigital number, since it uses as much as digits as its factorization.

20181247 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 896, while the sum is 25.

The square root of 20181247 is about 4492.3542825561. The cubic root of 20181247 is about 272.2592638629.

Adding to 20181247 its reverse (74218102), we get a palindrome (94399349).

The spelling of 20181247 in words is "twenty million, one hundred eighty-one thousand, two hundred forty-seven".