81584811 has 24 divisors (see below), whose sum is σ = 146924544. Its totient is φ = 42381360.

The previous prime is 81584807. The next prime is 81584837. The reversal of 81584811 is 11848518.

It is a happy number.

It is not a de Polignac number, because 81584811 - 2² = 81584807 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81584851) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 58171 + ... + 59556.

It is an arithmetic number, because the mean of its divisors is an integer number (6121856).

Almost surely, 2^81584811 is an apocalyptic number.

81584811 is a deficient number, since it is larger than the sum of its proper divisors (65339733).

81584811 is a wasteful number, since it uses less digits than its factorization.

81584811 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 117751 (or 117748 counting only the distinct ones).

The product of its digits is 10240, while the sum is 36.

The square root of 81584811 is about 9032.4310681012. The cubic root of 81584811 is about 433.7136632656.

The spelling of 81584811 in words is "eighty-one million, five hundred eighty-four thousand, eight hundred eleven".