81689049 has 24 divisors (see below), whose sum is σ = 128011520. Its totient is φ = 49898592.

The previous prime is 81689039. The next prime is 81689051. The reversal of 81689049 is 94098618.

It is not a de Polignac number, because 81689049 - 2⁴ = 81689033 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 81688995 and 81689013.

It is not an unprimeable number, because it can be changed into a prime (81689039) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 13752 + ... + 18774.

Almost surely, 2^81689049 is an apocalyptic number.

It is an amenable number.

81689049 is a deficient number, since it is larger than the sum of its proper divisors (46322471).

81689049 is a wasteful number, since it uses less digits than its factorization.

81689049 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5181 (or 5178 counting only the distinct ones).

The product of its (nonzero) digits is 124416, while the sum is 45.

The square root of 81689049 is about 9038.1994335155. The cubic root of 81689049 is about 433.8982981413.

The spelling of 81689049 in words is "eighty-one million, six hundred eighty-nine thousand, forty-nine".