81266050320 has 640 divisors, whose sum is σ = 317163700224. Its totient is φ = 16758669312.

The previous prime is 81266050309. The next prime is 81266050361. The reversal of 81266050320 is 2305066218.

It is a super-2 number, since 2×81266050320² (a number of 23 digits) contains 22 as substring.

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 127 ways as a sum of consecutive naturals, for example, 230215264 + ... + 230215616.

Almost surely, 2^81266050320 is an apocalyptic number.

81266050320 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81266050320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (158581850112).

81266050320 is an abundant number, since it is smaller than the sum of its proper divisors (235897649904).

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

81266050320 is a wasteful number, since it uses less digits than its factorization.

81266050320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 599 (or 593 counting only the distinct ones).

The product of its (nonzero) digits is 17280, while the sum is 33.

The spelling of 81266050320 in words is "eighty-one billion, two hundred sixty-six million, fifty thousand, three hundred twenty".