81488534400 has 2304 divisors, whose sum is σ = 397774540800. Its totient is φ = 15394406400.

The previous prime is 81488534359. The next prime is 81488534419. The reversal of 81488534400 is 443588418.

81488534400 is a `hidden beast` number, since 81 + 4 + 88 + 53 + 440 + 0 = 666.

It is a harmonic number, since the harmonic mean of its divisors is an integer.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 287 ways as a sum of consecutive naturals, for example, 1381161571 + ... + 1381161629.

It is an arithmetic number, because the mean of its divisors is an integer number (172645200).

Almost surely, 2^81488534400 is an apocalyptic number.

81488534400 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 81488534400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (198887270400).

81488534400 is an abundant number, since it is smaller than the sum of its proper divisors (316286006400).

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

81488534400 is a wasteful number, since it uses less digits than its factorization.

81488534400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 157 (or 137 counting only the distinct ones).

The product of its (nonzero) digits is 491520, while the sum is 45.

The spelling of 81488534400 in words is "eighty-one billion, four hundred eighty-eight million, five hundred thirty-four thousand, four hundred".