81801032525 has 24 divisors (see below), whose sum is σ = 102621556800. Its totient is φ = 64674896000.

The previous prime is 81801032507. The next prime is 81801032581. The reversal of 81801032525 is 52523010818.

It is a de Polignac number, because none of the positive numbers 2^k-81801032525 is a prime.

It is a super-2 number, since 2×81801032525² (a number of 23 digits) 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 (19) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 5463800 + ... + 5478750.

It is an arithmetic number, because the mean of its divisors is an integer number (4275898200).

Almost surely, 2^81801032525 is an apocalyptic number.

It is an amenable number.

81801032525 is a deficient number, since it is larger than the sum of its proper divisors (20820524275).

81801032525 is a wasteful number, since it uses less digits than its factorization.

81801032525 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17509 (or 17504 counting only the distinct ones).

The product of its (nonzero) digits is 19200, while the sum is 35.

The spelling of 81801032525 in words is "eighty-one billion, eight hundred one million, thirty-two thousand, five hundred twenty-five".