81321015360 has 1344 divisors, whose sum is σ = 325567365120. Its totient is φ = 17079828480.

The previous prime is 81321015319. The next prime is 81321015371. The reversal of 81321015360 is 6351012318.

It is a super-2 number, since 2×81321015360² (a number of 23 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is an unprimeable number.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 2197865262 + ... + 2197865298.

Almost surely, 2^81321015360 is an apocalyptic number.

81321015360 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 81321015360, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (162783682560).

81321015360 is an abundant number, since it is smaller than the sum of its proper divisors (244246349760).

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

81321015360 is a wasteful number, since it uses less digits than its factorization.

81321015360 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 156 (or 133 counting only the distinct ones).

The product of its (nonzero) digits is 4320, while the sum is 30.

Adding to 81321015360 its reverse (6351012318), we get a palindrome (87672027678).

The spelling of 81321015360 in words is "eighty-one billion, three hundred twenty-one million, fifteen thousand, three hundred sixty".