77958973638 has 144 divisors (see below), whose sum is σ = 218222361360. Its totient is φ = 20560490496.

The previous prime is 77958973607. The next prime is 77958973661. The reversal of 77958973638 is 83637985977.

77958973638 is a `hidden beast` number, since 7 + 7 + 9 + 589 + 7 + 3 + 6 + 38 = 666.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 360006 + ... + 534342.

It is an arithmetic number, because the mean of its divisors is an integer number (1515433065).

Almost surely, 2^77958973638 is an apocalyptic number.

77958973638 is a gapful number since it is divisible by the number (78) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 77958973638, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (109111180680).

77958973638 is an abundant number, since it is smaller than the sum of its proper divisors (140263387722).

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

77958973638 is a wasteful number, since it uses less digits than its factorization.

77958973638 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 174388 (or 174362 counting only the distinct ones).

The product of its digits is 480090240, while the sum is 72.

The spelling of 77958973638 in words is "seventy-seven billion, nine hundred fifty-eight million, nine hundred seventy-three thousand, six hundred thirty-eight".