81147049 has 2 divisors, whose sum is σ = 81147050. Its totient is φ = 81147048.

The previous prime is 81147047. The next prime is 81147061. The reversal of 81147049 is 94074118.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 74736025 + 6411024 = 8645^2 + 2532^2 .

It is a cyclic number.

It is not a de Polignac number, because 81147049 - 2¹ = 81147047 is a prime.

It is a super-2 number, since 2×81147049² = 13169687122816802, which contains 22 as substring.

Together with 81147047, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (81147041) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40573524 + 40573525.

It is an arithmetic number, because the mean of its divisors is an integer number (40573525).

Almost surely, 2^81147049 is an apocalyptic number.

It is an amenable number.

81147049 is a deficient number, since it is larger than the sum of its proper divisors (1).

81147049 is an equidigital number, since it uses as much as digits as its factorization.

81147049 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 8064, while the sum is 34.

The square root of 81147049 is about 9008.1656845331. The cubic root of 81147049 is about 432.9365416446.

The spelling of 81147049 in words is "eighty-one million, one hundred forty-seven thousand, forty-nine".