81472573440 has 832 divisors, whose sum is σ = 313370622720. Its totient is φ = 20256915456.

The previous prime is 81472573433. The next prime is 81472573459. The reversal of 81472573440 is 4437527418.

81472573440 is a `hidden beast` number, since 8 + 1 + 4 + 72 + 573 + 4 + 4 + 0 = 666.

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 63 ways as a sum of consecutive naturals, for example, 761425867 + ... + 761425973.

Almost surely, 2^81472573440 is an apocalyptic number.

81472573440 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 81472573440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (156685311360).

81472573440 is an abundant number, since it is smaller than the sum of its proper divisors (231898049280).

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

81472573440 is an equidigital number, since it uses as much as digits as its factorization.

81472573440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 174 (or 134 counting only the distinct ones).

The product of its (nonzero) digits is 752640, while the sum is 45.

The spelling of 81472573440 in words is "eighty-one billion, four hundred seventy-two million, five hundred seventy-three thousand, four hundred forty".