81901802340 has 72 divisors (see below), whose sum is σ = 248471616120. Its totient is φ = 21837302784.

The previous prime is 81901802329. The next prime is 81901802341. The reversal of 81901802340 is 4320810918.

It can be written as a sum of positive squares in 4 ways, for example, as 26940626496 + 54961175844 = 164136^2 + 234438^2 .

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 81901802295 and 81901802304.

It is not an unprimeable number, because it can be changed into a prime (81901802341) by changing a digit.

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 23 ways as a sum of consecutive naturals, for example, 1372812 + ... + 1431228.

Almost surely, 2^81901802340 is an apocalyptic number.

It is an amenable number.

81901802340 is an abundant number, since it is smaller than the sum of its proper divisors (166569813780).

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

81901802340 is a wasteful number, since it uses less digits than its factorization.

81901802340 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 66221 (or 66216 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 36.

The spelling of 81901802340 in words is "eighty-one billion, nine hundred one million, eight hundred two thousand, three hundred forty".