81775549 has 8 divisors (see below), whose sum is σ = 83244672. Its totient is φ = 80316000.

The previous prime is 81775537. The next prime is 81775553. The reversal of 81775549 is 94557718.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 81775549 - 2⁵ = 81775517 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 81775499 and 81775508.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81772549) 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 in 7 ways as a sum of consecutive naturals, for example, 16092 + ... + 20554.

It is an arithmetic number, because the mean of its divisors is an integer number (10405584).

Almost surely, 2^81775549 is an apocalyptic number.

It is an amenable number.

81775549 is a deficient number, since it is larger than the sum of its proper divisors (1469123).

81775549 is a wasteful number, since it uses less digits than its factorization.

81775549 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4787.

The product of its digits is 352800, while the sum is 46.

The square root of 81775549 is about 9042.9834125691. The cubic root of 81775549 is about 434.0513948069.

The spelling of 81775549 in words is "eighty-one million, seven hundred seventy-five thousand, five hundred forty-nine".