78744438668664 has 256 divisors, whose sum is σ = 234655170048000. Its totient is φ = 24395084461440.

The previous prime is 78744438668647. The next prime is 78744438668671. The reversal of 78744438668664 is 46686683444787.

78744438668664 is a `hidden beast` number, since 7 + 8 + 7 + 44 + 438 + 6 + 6 + 86 + 64 = 666.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 44359699 + ... + 46100669.

It is an arithmetic number, because the mean of its divisors is an integer number (916621758000).

Almost surely, 2^{78744438668664} is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 78744438668664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (117327585024000).

78744438668664 is an abundant number, since it is smaller than the sum of its proper divisors (155910731379336).

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

78744438668664 is a wasteful number, since it uses less digits than its factorization.

78744438668664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1741215 (or 1741205 counting only the distinct ones).

The product of its digits is 24970788864, while the sum is 81.

The spelling of 78744438668664 in words is "seventy-eight trillion, seven hundred forty-four billion, four hundred thirty-eight million, six hundred sixty-eight thousand, six hundred sixty-four".