81203662008 has 432 divisors, whose sum is σ = 270985211640. Its totient is φ = 21891098880.

The previous prime is 81203661971. The next prime is 81203662019. The reversal of 81203662008 is 80026630218.

81203662008 is a `hidden beast` number, since 8 + 1 + 20 + 3 + 6 + 620 + 0 + 8 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

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 107 ways as a sum of consecutive naturals, for example, 145787266 + ... + 145787822.

Almost surely, 2^81203662008 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 81203662008, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (135492605820).

81203662008 is an abundant number, since it is smaller than the sum of its proper divisors (189781549632).

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

81203662008 is a wasteful number, since it uses less digits than its factorization.

81203662008 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 688 (or 643 counting only the distinct ones).

The product of its (nonzero) digits is 27648, while the sum is 36.

The spelling of 81203662008 in words is "eighty-one billion, two hundred three million, six hundred sixty-two thousand, eight".