81155653 has 2 divisors, whose sum is σ = 81155654. Its totient is φ = 81155652.

The previous prime is 81155651. The next prime is 81155677. The reversal of 81155653 is 35655118.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 51365889 + 29789764 = 7167^2 + 5458^2 .

It is a cyclic number.

It is not a de Polignac number, because 81155653 - 2¹ = 81155651 is a prime.

Together with 81155651, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81155651) 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, 40577826 + 40577827.

It is an arithmetic number, because the mean of its divisors is an integer number (40577827).

Almost surely, 2^81155653 is an apocalyptic number.

It is an amenable number.

81155653 is a deficient number, since it is larger than the sum of its proper divisors (1).

81155653 is an equidigital number, since it uses as much as digits as its factorization.

81155653 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 18000, while the sum is 34.

The square root of 81155653 is about 9008.6432385793. The cubic root of 81155653 is about 432.9518424859.

The spelling of 81155653 in words is "eighty-one million, one hundred fifty-five thousand, six hundred fifty-three".