81046821 has 4 divisors (see below), whose sum is σ = 108062432. Its totient is φ = 54031212.

The previous prime is 81046783. The next prime is 81046843. The reversal of 81046821 is 12864018.

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 not a de Polignac number, because 81046821 - 2¹¹ = 81044773 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81046421) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13507801 + ... + 13507806.

It is an arithmetic number, because the mean of its divisors is an integer number (27015608).

Almost surely, 2^81046821 is an apocalyptic number.

It is an amenable number.

81046821 is a deficient number, since it is larger than the sum of its proper divisors (27015611).

81046821 is a wasteful number, since it uses less digits than its factorization.

81046821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27015610.

The product of its (nonzero) digits is 3072, while the sum is 30.

The square root of 81046821 is about 9002.6007908826. The cubic root of 81046821 is about 432.7582224011.

The spelling of 81046821 in words is "eighty-one million, forty-six thousand, eight hundred twenty-one".