82749521 has 4 divisors (see below), whose sum is σ = 84767844. Its totient is φ = 80731200.

The previous prime is 82749497. The next prime is 82749529. The reversal of 82749521 is 12594728.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 43824400 + 38925121 = 6620^2 + 6239^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-82749521 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (82749529) 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 in 3 ways as a sum of consecutive naturals, for example, 1009100 + ... + 1009181.

It is an arithmetic number, because the mean of its divisors is an integer number (21191961).

Almost surely, 2^82749521 is an apocalyptic number.

It is an amenable number.

82749521 is a deficient number, since it is larger than the sum of its proper divisors (2018323).

82749521 is a wasteful number, since it uses less digits than its factorization.

82749521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2018322.

The product of its digits is 40320, while the sum is 38.

The square root of 82749521 is about 9096.6763710709. The cubic root of 82749521 is about 435.7678269675.

The spelling of 82749521 in words is "eighty-two million, seven hundred forty-nine thousand, five hundred twenty-one".