81000001152 has 288 divisors, whose sum is σ = 280496139300. Its totient is φ = 22344376320.

The previous prime is 81000001141. The next prime is 81000001157. The reversal of 81000001152 is 25110000018.

It can be written as a sum of positive squares in 2 ways, for example, as 78055419456 + 2944581696 = 279384^2 + 54264^2 .

It is a tau number, because it is divible by the number of its divisors (288).

It is a super-2 number, since 2×81000001152² (a number of 23 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is not an unprimeable number, because it can be changed into a prime (81000001157) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 1612252 + ... + 1661732.

Almost surely, 2^81000001152 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 81000001152, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (140248069650).

81000001152 is an abundant number, since it is smaller than the sum of its proper divisors (199496138148).

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

81000001152 is a wasteful number, since it uses less digits than its factorization.

81000001152 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 49544 (or 49522 counting only the distinct ones).

The product of its (nonzero) digits is 80, while the sum is 18.

The spelling of 81000001152 in words is "eighty-one billion, one thousand, one hundred fifty-two".