81390059520 has 1440 divisors, whose sum is σ = 361470864384. Its totient is φ = 15225323520.

The previous prime is 81390059519. The next prime is 81390059651. The reversal of 81390059520 is 2595009318.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 3538698229 + ... + 3538698251.

Almost surely, 2^81390059520 is an apocalyptic number.

81390059520 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 81390059520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (180735432192).

81390059520 is an abundant number, since it is smaller than the sum of its proper divisors (280080804864).

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

81390059520 is a wasteful number, since it uses less digits than its factorization.

81390059520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 105 (or 68 counting only the distinct ones).

The product of its (nonzero) digits is 97200, while the sum is 42.

The spelling of 81390059520 in words is "eighty-one billion, three hundred ninety million, fifty-nine thousand, five hundred twenty".