81273393630 has 384 divisors, whose sum is σ = 268667642880. Its totient is φ = 17394600960.

The previous prime is 81273393623. The next prime is 81273393647. The reversal of 81273393630 is 3639337218.

81273393630 is a `hidden beast` number, since 8 + 1 + 2 + 7 + 3 + 3 + 9 + 3 + 630 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

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 191 ways as a sum of consecutive naturals, for example, 7987186 + ... + 7997354.

It is an arithmetic number, because the mean of its divisors is an integer number (699655320).

Almost surely, 2^81273393630 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81273393630, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (134333821440).

81273393630 is an abundant number, since it is smaller than the sum of its proper divisors (187394249250).

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

81273393630 is a wasteful number, since it uses less digits than its factorization.

81273393630 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10238 (or 10226 counting only the distinct ones).

The product of its (nonzero) digits is 489888, while the sum is 45.

The spelling of 81273393630 in words is "eighty-one billion, two hundred seventy-three million, three hundred ninety-three thousand, six hundred thirty".