78641280 has 320 divisors, whose sum is σ = 295467480. Its totient is φ = 19906560.

The previous prime is 78641273. The next prime is 78641287. The reversal of 78641280 is 8214687.

78641280 is a `hidden beast` number, since 7 + 8 + 641 + 2 + 8 + 0 = 666.

It is an interprime number because it is at equal distance from previous prime (78641273) and next prime (78641287).

It can be written as a sum of positive squares in 4 ways, for example, as 59351616 + 19289664 = 7704^2 + 4392^2 .

It is a tau number, because it is divible by the number of its divisors (320).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78641287) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 1918060 + ... + 1918100.

Almost surely, 2^78641280 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 78641280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (147733740).

78641280 is an abundant number, since it is smaller than the sum of its proper divisors (216826200).

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

78641280 is a wasteful number, since it uses less digits than its factorization.

78641280 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 109 (or 88 counting only the distinct ones).

The product of its (nonzero) digits is 21504, while the sum is 36.

The square root of 78641280 is about 8867.9918809164. The cubic root of 78641280 is about 428.4336013943.

The spelling of 78641280 in words is "seventy-eight million, six hundred forty-one thousand, two hundred eighty".