81218171147 has 2 divisors, whose sum is σ = 81218171148. Its totient is φ = 81218171146.

The previous prime is 81218171137. The next prime is 81218171201. The reversal of 81218171147 is 74117181218.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81218171147 - 2⁴ = 81218171131 is a prime.

It is not a weakly prime, because it can be changed into another prime (81218171137) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40609085573 + 40609085574.

It is an arithmetic number, because the mean of its divisors is an integer number (40609085574).

Almost surely, 2^81218171147 is an apocalyptic number.

81218171147 is a deficient number, since it is larger than the sum of its proper divisors (1).

81218171147 is an equidigital number, since it uses as much as digits as its factorization.

81218171147 is an evil number, because the sum of its binary digits is even.

The product of its digits is 25088, while the sum is 41.

The spelling of 81218171147 in words is "eighty-one billion, two hundred eighteen million, one hundred seventy-one thousand, one hundred forty-seven".