81208427520 has 352 divisors, whose sum is σ = 284203514880. Its totient is φ = 19627868160.

The previous prime is 81208427519. The next prime is 81208427539. The reversal of 81208427520 is 2572480218.

It is a tau number, because it is divible by the number of its divisors (352).

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 88365621 + ... + 88366539.

Almost surely, 2^81208427520 is an apocalyptic number.

81208427520 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 81208427520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (142101757440).

81208427520 is an abundant number, since it is smaller than the sum of its proper divisors (202995087360).

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

81208427520 is a wasteful number, since it uses less digits than its factorization.

81208427520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1481 (or 1463 counting only the distinct ones).

The product of its (nonzero) digits is 71680, while the sum is 39.

The spelling of 81208427520 in words is "eighty-one billion, two hundred eight million, four hundred twenty-seven thousand, five hundred twenty".