81240977152 has 72 divisors (see below), whose sum is σ = 164942583120. Its totient is φ = 39929978880.

The previous prime is 81240977149. The next prime is 81240977171. The reversal of 81240977152 is 25177904218.

It is a super-2 number, since 2×81240977152² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3931327 + ... + 3951937.

It is an arithmetic number, because the mean of its divisors is an integer number (2290869210).

Almost surely, 2^81240977152 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 81240977152, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (82471291560).

81240977152 is an abundant number, since it is smaller than the sum of its proper divisors (83701605968).

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

81240977152 is a wasteful number, since it uses less digits than its factorization.

81240977152 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20889 (or 20875 counting only the distinct ones).

The product of its (nonzero) digits is 282240, while the sum is 46.

The spelling of 81240977152 in words is "eighty-one billion, two hundred forty million, nine hundred seventy-seven thousand, one hundred fifty-two".