81378036732384 has 576 divisors, whose sum is σ = 276698801433600. Its totient is φ = 22207624298496.

The previous prime is 81378036732361. The next prime is 81378036732409. The reversal of 81378036732384 is 48323763087318.

It is a happy number.

81378036732384 is a `hidden beast` number, since 8 + 1 + 37 + 8 + 0 + 367 + 3 + 238 + 4 = 666.

It is a Harshad number since it is a multiple of its sum of digits (63).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 649252632 + ... + 649377960.

It is an arithmetic number, because the mean of its divisors is an integer number (480379863600).

Almost surely, 2^{81378036732384} is an apocalyptic number.

81378036732384 is a gapful number since it is divisible by the number (84) 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 81378036732384, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (138349400716800).

81378036732384 is an abundant number, since it is smaller than the sum of its proper divisors (195320764701216).

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

81378036732384 is a wasteful number, since it uses less digits than its factorization.

81378036732384 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 125567 (or 125556 counting only the distinct ones).

The product of its (nonzero) digits is 97542144, while the sum is 63.

The spelling of 81378036732384 in words is "eighty-one trillion, three hundred seventy-eight billion, thirty-six million, seven hundred thirty-two thousand, three hundred eighty-four".