81465523200 has 660 divisors, whose sum is σ = 319540007952. Its totient is φ = 20437401600.

The previous prime is 81465523199. The next prime is 81465523267. The reversal of 81465523200 is 232556418.

81465523200 is a `hidden beast` number, since 81 + 4 + 6 + 552 + 3 + 20 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 59 ways as a sum of consecutive naturals, for example, 35250045 + ... + 35252355.

Almost surely, 2^81465523200 is an apocalyptic number.

81465523200 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 81465523200, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (159770003976).

81465523200 is an abundant number, since it is smaller than the sum of its proper divisors (238074484752).

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

81465523200 is a wasteful number, since it uses less digits than its factorization.

81465523200 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2370 (or 2338 counting only the distinct ones).

The product of its (nonzero) digits is 57600, while the sum is 36.

The spelling of 81465523200 in words is "eighty-one billion, four hundred sixty-five million, five hundred twenty-three thousand, two hundred".