81302556 has 24 divisors (see below), whose sum is σ = 190204560. Its totient is φ = 27029632.

The previous prime is 81302521. The next prime is 81302581. The reversal of 81302556 is 65520318.

It is a super-2 number, since 2×81302556² = 13220211224266272, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4041 + ... + 13376.

It is an arithmetic number, because the mean of its divisors is an integer number (7925190).

Almost surely, 2^81302556 is an apocalyptic number.

It is an amenable number.

81302556 is an abundant number, since it is smaller than the sum of its proper divisors (108902004).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81302556 is a wasteful number, since it uses less digits than its factorization.

81302556 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17813 (or 17811 counting only the distinct ones).

The product of its (nonzero) digits is 7200, while the sum is 30.

The square root of 81302556 is about 9016.7929997311. The cubic root of 81302556 is about 433.2129193369.

The spelling of 81302556 in words is "eighty-one million, three hundred two thousand, five hundred fifty-six".