81169651 has 2 divisors, whose sum is σ = 81169652. Its totient is φ = 81169650.

The previous prime is 81169643. The next prime is 81169657. The reversal of 81169651 is 15696118.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81169651 - 2³ = 81169643 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 81169651.

It is not a weakly prime, because it can be changed into another prime (81169657) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40584825 + 40584826.

It is an arithmetic number, because the mean of its divisors is an integer number (40584826).

Almost surely, 2^81169651 is an apocalyptic number.

81169651 is a deficient number, since it is larger than the sum of its proper divisors (1).

81169651 is an equidigital number, since it uses as much as digits as its factorization.

81169651 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 81169651 is about 9009.4201256241. The cubic root of 81169651 is about 432.9767333849.

The spelling of 81169651 in words is "eighty-one million, one hundred sixty-nine thousand, six hundred fifty-one".