81806430339072 has 896 divisors, whose sum is σ = 257509542263040. Its totient is φ = 25942228992000.

The previous prime is 81806430339061. The next prime is 81806430339107. The reversal of 81806430339072 is 27093303460818.

81806430339072 is a `hidden beast` number, since 8 + 180 + 6 + 4 + 3 + 0 + 3 + 390 + 72 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is an unprimeable number.

It is a polite number, since it can be written in 55 ways as a sum of consecutive naturals, for example, 45171965047 + ... + 45171966857.

Almost surely, 2^{81806430339072} 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 81806430339072, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (128754771131520).

81806430339072 is an abundant number, since it is smaller than the sum of its proper divisors (175703111923968).

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

81806430339072 is an frugal number, since it uses more digits than its factorization.

81806430339072 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1951 (or 1908 counting only the distinct ones).

The product of its (nonzero) digits is 5225472, while the sum is 54.

The spelling of 81806430339072 in words is "eighty-one trillion, eight hundred six billion, four hundred thirty million, three hundred thirty-nine thousand, seventy-two".