81002439 has 36 divisors (see below), whose sum is σ = 137808216. Its totient is φ = 45708768.

The previous prime is 81002437. The next prime is 81002443. The reversal of 81002439 is 93420018.

It is not a de Polignac number, because 81002439 - 2¹ = 81002437 is a prime.

It is a super-2 number, since 2×81002439² = 13122790247897442, which contains 22 as substring.

81002439 is a modest number, since divided by 2439 gives 810 as remainder.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81002431) 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 35 ways as a sum of consecutive naturals, for example, 35497 + ... + 37709.

It is an arithmetic number, because the mean of its divisors is an integer number (3828006).

Almost surely, 2^81002439 is an apocalyptic number.

81002439 is a deficient number, since it is larger than the sum of its proper divisors (56805777).

81002439 is a wasteful number, since it uses less digits than its factorization.

81002439 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2316 (or 2306 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 27.

The square root of 81002439 is about 9000.1354989800. The cubic root of 81002439 is about 432.6792138223.

The spelling of 81002439 in words is "eighty-one million, two thousand, four hundred thirty-nine".