81468729 has 6 divisors (see below), whose sum is σ = 117677066. Its totient is φ = 54312480.

The previous prime is 81468701. The next prime is 81468757. The reversal of 81468729 is 92786418.

It is an interprime number because it is at equal distance from previous prime (81468701) and next prime (81468757).

It can be written as a sum of positive squares in only one way, i.e., 68508729 + 12960000 = 8277^2 + 3600^2 .

It is not a de Polignac number, because 81468729 - 2⁷ = 81468601 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81468929) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 4526032 + ... + 4526049.

Almost surely, 2^81468729 is an apocalyptic number.

It is an amenable number.

81468729 is a deficient number, since it is larger than the sum of its proper divisors (36208337).

81468729 is a wasteful number, since it uses less digits than its factorization.

81468729 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9052087 (or 9052084 counting only the distinct ones).

The product of its digits is 193536, while the sum is 45.

The square root of 81468729 is about 9026.0029359623. The cubic root of 81468729 is about 433.5078641470.

The spelling of 81468729 in words is "eighty-one million, four hundred sixty-eight thousand, seven hundred twenty-nine".