81042869 has 4 divisors (see below), whose sum is σ = 84566496. Its totient is φ = 77519244.

The previous prime is 81042853. The next prime is 81042881. The reversal of 81042869 is 96824018.

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, and also an emirpimes, since its reverse is a distinct semiprime: 96824018 = 2 ⋅48412009.

It is a cyclic number.

It is not a de Polignac number, because 81042869 - 2⁴ = 81042853 is a prime.

It is a super-2 number, since 2×81042869² = 13135893231502322, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81042889) 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, 1761779 + ... + 1761824.

It is an arithmetic number, because the mean of its divisors is an integer number (21141624).

Almost surely, 2^81042869 is an apocalyptic number.

It is an amenable number.

81042869 is a deficient number, since it is larger than the sum of its proper divisors (3523627).

81042869 is a wasteful number, since it uses less digits than its factorization.

81042869 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3523626.

The product of its (nonzero) digits is 27648, while the sum is 38.

The square root of 81042869 is about 9002.3812960794. The cubic root of 81042869 is about 432.7511882436.

The spelling of 81042869 in words is "eighty-one million, forty-two thousand, eight hundred sixty-nine".