81074729 has 4 divisors (see below), whose sum is σ = 85341840. Its totient is φ = 76807620.

The previous prime is 81074723. The next prime is 81074731. The reversal of 81074729 is 92747018.

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 81074729 - 2⁴ = 81074713 is a prime.

It is a super-2 number, since 2×81074729² = 13146223364846882, which contains 22 as substring.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 81074692 and 81074701.

It is not an unprimeable number, because it can be changed into a prime (81074723) 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, 2133527 + ... + 2133564.

It is an arithmetic number, because the mean of its divisors is an integer number (21335460).

Almost surely, 2^81074729 is an apocalyptic number.

It is an amenable number.

81074729 is a deficient number, since it is larger than the sum of its proper divisors (4267111).

81074729 is a wasteful number, since it uses less digits than its factorization.

81074729 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4267110.

The product of its (nonzero) digits is 28224, while the sum is 38.

The square root of 81074729 is about 9004.1506540040. The cubic root of 81074729 is about 432.8078892904.

The spelling of 81074729 in words is "eighty-one million, seventy-four thousand, seven hundred twenty-nine".