81722911 has 2 divisors, whose sum is σ = 81722912. Its totient is φ = 81722910.

The previous prime is 81722897. The next prime is 81722929. The reversal of 81722911 is 11922718.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81722911 - 2¹³ = 81714719 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81722941) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40861455 + 40861456.

It is an arithmetic number, because the mean of its divisors is an integer number (40861456).

Almost surely, 2^81722911 is an apocalyptic number.

81722911 is a deficient number, since it is larger than the sum of its proper divisors (1).

81722911 is an equidigital number, since it uses as much as digits as its factorization.

81722911 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2016, while the sum is 31.

The square root of 81722911 is about 9040.0725107711. The cubic root of 81722911 is about 433.9582434856.

The spelling of 81722911 in words is "eighty-one million, seven hundred twenty-two thousand, nine hundred eleven".