81088649 has 2 divisors, whose sum is σ = 81088650. Its totient is φ = 81088648.

The previous prime is 81088643. The next prime is 81088663. The reversal of 81088649 is 94688018.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 78198649 + 2890000 = 8843^2 + 1700^2 .

It is a cyclic number.

It is not a de Polignac number, because 81088649 - 2⁸ = 81088393 is a prime.

It is a super-3 number, since 3×81088649³ (a number of 25 digits) contains 333 as substring.

It is not a weakly prime, because it can be changed into another prime (81088643) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40544324 + 40544325.

It is an arithmetic number, because the mean of its divisors is an integer number (40544325).

Almost surely, 2^81088649 is an apocalyptic number.

It is an amenable number.

81088649 is a deficient number, since it is larger than the sum of its proper divisors (1).

81088649 is an equidigital number, since it uses as much as digits as its factorization.

81088649 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 110592, while the sum is 44.

The square root of 81088649 is about 9004.9235976770. The cubic root of 81088649 is about 432.8326579663.

The spelling of 81088649 in words is "eighty-one million, eighty-eight thousand, six hundred forty-nine".