81071202240 has 560 divisors, whose sum is σ = 343929687552. Its totient is φ = 17723971584.

The previous prime is 81071202203. The next prime is 81071202241. The reversal of 81071202240 is 4220217018.

It is a tau number, because it is divible by the number of its divisors (560).

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81071202241) by changing a digit.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 4163407 + ... + 4182833.

Almost surely, 2^81071202240 is an apocalyptic number.

81071202240 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 81071202240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (171964843776).

81071202240 is an abundant number, since it is smaller than the sum of its proper divisors (262858485312).

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

81071202240 is a wasteful number, since it uses less digits than its factorization.

81071202240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19486 (or 19467 counting only the distinct ones).

The product of its (nonzero) digits is 1792, while the sum is 27.

Adding to 81071202240 its reverse (4220217018), we get a palindrome (85291419258).

The spelling of 81071202240 in words is "eighty-one billion, seventy-one million, two hundred two thousand, two hundred forty".