81583121 has 8 divisors (see below), whose sum is σ = 83467560. Its totient is φ = 79719552.

The previous prime is 81583097. The next prime is 81583123. The reversal of 81583121 is 12138518.

It can be written as a sum of positive squares in 4 ways, for example, as 7623121 + 73960000 = 2761^2 + 8600^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 81583121 - 2⁶ = 81583057 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81583123) 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 7 ways as a sum of consecutive naturals, for example, 2831 + ... + 13083.

It is an arithmetic number, because the mean of its divisors is an integer number (10433445).

Almost surely, 2^81583121 is an apocalyptic number.

It is an amenable number.

81583121 is a deficient number, since it is larger than the sum of its proper divisors (1884439).

81583121 is a wasteful number, since it uses less digits than its factorization.

81583121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10435.

The product of its digits is 1920, while the sum is 29.

The square root of 81583121 is about 9032.3375158372. The cubic root of 81583121 is about 433.7106685041.

The spelling of 81583121 in words is "eighty-one million, five hundred eighty-three thousand, one hundred twenty-one".