81459729 has 16 divisors (see below), whose sum is σ = 129964800. Its totient is φ = 50128848.

The previous prime is 81459709. The next prime is 81459737. The reversal of 81459729 is 92795418.

It is not a de Polignac number, because 81459729 - 2⁸ = 81459473 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81459709) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 115689 + ... + 116390.

It is an arithmetic number, because the mean of its divisors is an integer number (8122800).

Almost surely, 2^81459729 is an apocalyptic number.

It is an amenable number.

81459729 is a deficient number, since it is larger than the sum of its proper divisors (48505071).

81459729 is a wasteful number, since it uses less digits than its factorization.

81459729 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 232101 (or 232095 counting only the distinct ones).

The product of its digits is 181440, while the sum is 45.

The square root of 81459729 is about 9025.5043626381. The cubic root of 81459729 is about 433.4919000893.

The spelling of 81459729 in words is "eighty-one million, four hundred fifty-nine thousand, seven hundred twenty-nine".