81280581 has 8 divisors (see below), whose sum is σ = 109991904. Its totient is φ = 53378160.

The previous prime is 81280547. The next prime is 81280603. The reversal of 81280581 is 18508218.

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

It is a de Polignac number, because none of the positive numbers 2^k-81280581 is a prime.

It is a super-2 number, since 2×81280581² = 13213065695395122, which contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81280541) 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, 201990 + ... + 202391.

It is an arithmetic number, because the mean of its divisors is an integer number (13748988).

Almost surely, 2^81280581 is an apocalyptic number.

It is an amenable number.

81280581 is a deficient number, since it is larger than the sum of its proper divisors (28711323).

81280581 is a wasteful number, since it uses less digits than its factorization.

81280581 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 404451.

The product of its (nonzero) digits is 5120, while the sum is 33.

The square root of 81280581 is about 9015.5743577434. The cubic root of 81280581 is about 433.1738852556.

Adding to 81280581 its reverse (18508218), we get a palindrome (99788799).

The spelling of 81280581 in words is "eighty-one million, two hundred eighty thousand, five hundred eighty-one".