81532191662400 has 672 divisors, whose sum is σ = 275416797196800. Its totient is φ = 21108184064000.

The previous prime is 81532191662377. The next prime is 81532191662417. The reversal of 81532191662400 is 426619123518.

It is a Harshad number since it is a multiple of its sum of digits (48).

It is a self number, because there is not a number n which added to its sum of digits gives 81532191662400.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 11984737399 + ... + 11984744201.

It is an arithmetic number, because the mean of its divisors is an integer number (409846424400).

Almost surely, 2^{81532191662400} is an apocalyptic number.

81532191662400 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 81532191662400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (137708398598400).

81532191662400 is an abundant number, since it is smaller than the sum of its proper divisors (193884605534400).

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

81532191662400 is a wasteful number, since it uses less digits than its factorization.

81532191662400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7407 (or 7392 counting only the distinct ones).

The product of its (nonzero) digits is 622080, while the sum is 48.

The spelling of 81532191662400 in words is "eighty-one trillion, five hundred thirty-two billion, one hundred ninety-one million, six hundred sixty-two thousand, four hundred".