81348157440 has 672 divisors, whose sum is σ = 319448054016. Its totient is φ = 19694223360.

The previous prime is 81348157391. The next prime is 81348157447. The reversal of 81348157440 is 4475184318.

81348157440 is a `hidden beast` number, since 8 + 1 + 34 + 8 + 1 + 574 + 40 = 666.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81348157447) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 109485709 + ... + 109486451.

It is an arithmetic number, because the mean of its divisors is an integer number (475369128).

Almost surely, 2^81348157440 is an apocalyptic number.

81348157440 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 81348157440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (159724027008).

81348157440 is an abundant number, since it is smaller than the sum of its proper divisors (238099896576).

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

81348157440 is an equidigital number, since it uses as much as digits as its factorization.

81348157440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 800 (or 764 counting only the distinct ones).

The product of its (nonzero) digits is 430080, while the sum is 45.

The spelling of 81348157440 in words is "eighty-one billion, three hundred forty-eight million, one hundred fifty-seven thousand, four hundred forty".