81990247248 has 960 divisors, whose sum is σ = 310867603200. Its totient is φ = 20605777920.

The previous prime is 81990247247. The next prime is 81990247271. The reversal of 81990247248 is 84274209918.

81990247248 is a `hidden beast` number, since 81 + 9 + 90 + 2 + 472 + 4 + 8 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a junction number, because it is equal to n+sod(n) for n = 81990247194 and 81990247203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81990247247) by changing a digit.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 1906749915 + ... + 1906749957.

It is an arithmetic number, because the mean of its divisors is an integer number (323820420).

Almost surely, 2^81990247248 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 81990247248, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (155433801600).

81990247248 is an abundant number, since it is smaller than the sum of its proper divisors (228877355952).

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

81990247248 is a wasteful number, since it uses less digits than its factorization.

81990247248 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 154 (or 109 counting only the distinct ones).

The product of its (nonzero) digits is 2322432, while the sum is 54.

The spelling of 81990247248 in words is "eighty-one billion, nine hundred ninety million, two hundred forty-seven thousand, two hundred forty-eight".