81439089 has 4 divisors (see below), whose sum is σ = 108585456. Its totient is φ = 54292724.

The previous prime is 81439081. The next prime is 81439123. The reversal of 81439089 is 98093418.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 81439089 - 2³ = 81439081 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 81439089.

It is not an unprimeable number, because it can be changed into a prime (81439081) 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, 13573179 + ... + 13573184.

It is an arithmetic number, because the mean of its divisors is an integer number (27146364).

Almost surely, 2^81439089 is an apocalyptic number.

It is an amenable number.

81439089 is a deficient number, since it is larger than the sum of its proper divisors (27146367).

81439089 is a wasteful number, since it uses less digits than its factorization.

81439089 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27146366.

The product of its (nonzero) digits is 62208, while the sum is 42.

The square root of 81439089 is about 9024.3608637953. The cubic root of 81439089 is about 433.4552847428.

It can be divided in two parts, 814 and 39089, that added together give a triangular number (39903 = T₂₈₂).

The spelling of 81439089 in words is "eighty-one million, four hundred thirty-nine thousand, eighty-nine".