81179851 has 2 divisors, whose sum is σ = 81179852. Its totient is φ = 81179850.

The previous prime is 81179849. The next prime is 81179863. The reversal of 81179851 is 15897118.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81179851 - 2¹ = 81179849 is a prime.

Together with 81179849, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (81179831) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40589925 + 40589926.

It is an arithmetic number, because the mean of its divisors is an integer number (40589926).

Almost surely, 2^81179851 is an apocalyptic number.

81179851 is a deficient number, since it is larger than the sum of its proper divisors (1).

81179851 is an equidigital number, since it uses as much as digits as its factorization.

81179851 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 20160, while the sum is 40.

The square root of 81179851 is about 9009.9861820094. The cubic root of 81179851 is about 432.9948689715.

The spelling of 81179851 in words is "eighty-one million, one hundred seventy-nine thousand, eight hundred fifty-one".