71978976405 has 64 divisors (see below), whose sum is σ = 146443921920. Its totient is φ = 32859468288.

The previous prime is 71978976403. The next prime is 71978976449. The reversal of 71978976405 is 50467987917.

71978976405 is a `hidden beast` number, since 71 + 9 + 78 + 97 + 6 + 405 = 666.

It is not a de Polignac number, because 71978976405 - 2¹ = 71978976403 is a prime.

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

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (71978976403) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 640729 + ... + 744641.

It is an arithmetic number, because the mean of its divisors is an integer number (2288186280).

Almost surely, 2^71978976405 is an apocalyptic number.

It is an amenable number.

71978976405 is an abundant number, since it is smaller than the sum of its proper divisors (74464945515).

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

71978976405 is a wasteful number, since it uses less digits than its factorization.

71978976405 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 104667 (or 104661 counting only the distinct ones).

The product of its (nonzero) digits is 26671680, while the sum is 63.

The spelling of 71978976405 in words is "seventy-one billion, nine hundred seventy-eight million, nine hundred seventy-six thousand, four hundred five".