81823472640 has 1584 divisors, whose sum is σ = 374001638400. Its totient is φ = 16148201472.

The previous prime is 81823472623. The next prime is 81823472657. The reversal of 81823472640 is 4627432818.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (81823472623) and next prime (81823472657).

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

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 1035740121 + ... + 1035740199.

Almost surely, 2^81823472640 is an apocalyptic number.

81823472640 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 81823472640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (187000819200).

81823472640 is an abundant number, since it is smaller than the sum of its proper divisors (292178165760).

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

81823472640 is a wasteful number, since it uses less digits than its factorization.

81823472640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 162 (or 128 counting only the distinct ones).

The product of its (nonzero) digits is 516096, while the sum is 45.

The spelling of 81823472640 in words is "eighty-one billion, eight hundred twenty-three million, four hundred seventy-two thousand, six hundred forty".