81959754240 has 1440 divisors, whose sum is σ = 366342552576. Its totient is φ = 16562257920.

The previous prime is 81959754229. The next prime is 81959754319. The reversal of 81959754240 is 4245795918.

It is a happy number.

81959754240 is a `hidden beast` number, since 8 + 1 + 9 + 5 + 97 + 542 + 4 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (1440).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 844945872 + ... + 844945968.

Almost surely, 2^81959754240 is an apocalyptic number.

81959754240 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 81959754240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (183171276288).

81959754240 is an abundant number, since it is smaller than the sum of its proper divisors (284382798336).

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

81959754240 is a wasteful number, since it uses less digits than its factorization.

81959754240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 190 (or 158 counting only the distinct ones).

The product of its (nonzero) digits is 3628800, while the sum is 54.

The spelling of 81959754240 in words is "eighty-one billion, nine hundred fifty-nine million, seven hundred fifty-four thousand, two hundred forty".