81020279648 has 288 divisors, whose sum is σ = 208273250304. Its totient is φ = 30336768000.

The previous prime is 81020279597. The next prime is 81020279689. The reversal of 81020279648 is 84697202018.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 177287036 + ... + 177287492.

It is an arithmetic number, because the mean of its divisors is an integer number (723171008).

Almost surely, 2^81020279648 is an apocalyptic number.

81020279648 is a gapful number since it is divisible by the number (88) 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 81020279648, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (104136625152).

81020279648 is an abundant number, since it is smaller than the sum of its proper divisors (127252970656).

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

81020279648 is a wasteful number, since it uses less digits than its factorization.

81020279648 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 738 (or 719 counting only the distinct ones).

The product of its (nonzero) digits is 387072, while the sum is 47.

The spelling of 81020279648 in words is "eighty-one billion, twenty million, two hundred seventy-nine thousand, six hundred forty-eight".