81675352520 has 64 divisors (see below), whose sum is σ = 188840635200. Its totient is φ = 31769591040.

The previous prime is 81675352513. The next prime is 81675352559. The reversal of 81675352520 is 2525357618.

It is a Cunningham number, because it is equal to 285789²-1.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2843591 + ... + 2872169.

It is an arithmetic number, because the mean of its divisors is an integer number (2950634925).

Almost surely, 2^81675352520 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81675352520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (94420317600).

81675352520 is an abundant number, since it is smaller than the sum of its proper divisors (107165282680).

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

81675352520 is a wasteful number, since it uses less digits than its factorization.

81675352520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30558 (or 30554 counting only the distinct ones).

The product of its (nonzero) digits is 504000, while the sum is 44.

The spelling of 81675352520 in words is "eighty-one billion, six hundred seventy-five million, three hundred fifty-two thousand, five hundred twenty".