81020625560 has 32 divisors (see below), whose sum is σ = 208338752160. Its totient is φ = 27778500096.

The previous prime is 81020625509. The next prime is 81020625563. The reversal of 81020625560 is 6552602018.

It is a super-2 number, since 2×81020625560² (a number of 23 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (35).

It is a self number, because there is not a number n which added to its sum of digits gives 81020625560.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81020625563) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 144679409 + ... + 144679968.

It is an arithmetic number, because the mean of its divisors is an integer number (6510586005).

Almost surely, 2^81020625560 is an apocalyptic number.

It is an amenable number.

81020625560 is an abundant number, since it is smaller than the sum of its proper divisors (127318126600).

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

81020625560 is a wasteful number, since it uses less digits than its factorization.

81020625560 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 289359395 (or 289359391 counting only the distinct ones).

The product of its (nonzero) digits is 28800, while the sum is 35.

The spelling of 81020625560 in words is "eighty-one billion, twenty million, six hundred twenty-five thousand, five hundred sixty".