81669151 has 2 divisors, whose sum is σ = 81669152. Its totient is φ = 81669150.

The previous prime is 81669149. The next prime is 81669187. The reversal of 81669151 is 15196618.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81669151 - 2¹ = 81669149 is a prime.

Together with 81669149, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 81669151.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81669121) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40834575 + 40834576.

It is an arithmetic number, because the mean of its divisors is an integer number (40834576).

Almost surely, 2^81669151 is an apocalyptic number.

81669151 is a deficient number, since it is larger than the sum of its proper divisors (1).

81669151 is an equidigital number, since it uses as much as digits as its factorization.

81669151 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 12960, while the sum is 37.

The square root of 81669151 is about 9037.0985941285. The cubic root of 81669151 is about 433.8630653101.

The spelling of 81669151 in words is "eighty-one million, six hundred sixty-nine thousand, one hundred fifty-one".