78536640 has 448 divisors, whose sum is σ = 327720960. Its totient is φ = 15482880.

The previous prime is 78536629. The next prime is 78536641. The reversal of 78536640 is 4663587.

It is a tau number, because it is divible by the number of its divisors (448).

It is a Harshad number since it is a multiple of its sum of digits (39).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78536641) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 2533425 + ... + 2533455.

It is an arithmetic number, because the mean of its divisors is an integer number (731520).

Almost surely, 2^78536640 is an apocalyptic number.

78536640 is a gapful number since it is divisible by the number (70) 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 78536640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (163860480).

78536640 is an abundant number, since it is smaller than the sum of its proper divisors (249184320).

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

78536640 is a wasteful number, since it uses less digits than its factorization.

78536640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 100 (or 90 counting only the distinct ones).

The product of its (nonzero) digits is 120960, while the sum is 39.

The square root of 78536640 is about 8862.0900469359. The cubic root of 78536640 is about 428.2434926248.

The spelling of 78536640 in words is "seventy-eight million, five hundred thirty-six thousand, six hundred forty".