81469439 has 4 divisors (see below), whose sum is σ = 84278760. Its totient is φ = 78660120.

The previous prime is 81469433. The next prime is 81469441. The reversal of 81469439 is 93496418.

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

It is a cyclic number.

It is not a de Polignac number, because 81469439 - 2²⁴ = 64692223 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 81469439.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81469433) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1404617 + ... + 1404674.

It is an arithmetic number, because the mean of its divisors is an integer number (21069690).

Almost surely, 2^81469439 is an apocalyptic number.

81469439 is a deficient number, since it is larger than the sum of its proper divisors (2809321).

81469439 is a wasteful number, since it uses less digits than its factorization.

81469439 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2809320.

The product of its digits is 186624, while the sum is 44.

The square root of 81469439 is about 9026.0422666859. The cubic root of 81469439 is about 433.5091234837.

The spelling of 81469439 in words is "eighty-one million, four hundred sixty-nine thousand, four hundred thirty-nine".