81663250452 has 72 divisors (see below), whose sum is σ = 222001020864. Its totient is φ = 23296186368.

The previous prime is 81663250433. The next prime is 81663250457. The reversal of 81663250452 is 25405236618.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81663250457) by changing a digit.

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 23 ways as a sum of consecutive naturals, for example, 273108 + ... + 487764.

It is an arithmetic number, because the mean of its divisors is an integer number (3083347512).

Almost surely, 2^81663250452 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 81663250452, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (111000510432).

81663250452 is an abundant number, since it is smaller than the sum of its proper divisors (140337770412).

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

81663250452 is a wasteful number, since it uses less digits than its factorization.

81663250452 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 215325 (or 215316 counting only the distinct ones).

The product of its (nonzero) digits is 345600, while the sum is 42.

The spelling of 81663250452 in words is "eighty-one billion, six hundred sixty-three million, two hundred fifty thousand, four hundred fifty-two".