78644945 has 8 divisors (see below), whose sum is σ = 94421544. Its totient is φ = 62884224.

The previous prime is 78644927. The next prime is 78644947. The reversal of 78644945 is 54944687.

It can be written as a sum of positive squares in 4 ways, for example, as 3094081 + 75550864 = 1759^2 + 8692^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-78644945 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 78644945.

It is not an unprimeable number, because it can be changed into a prime (78644947) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 17357 + ... + 21413.

It is an arithmetic number, because the mean of its divisors is an integer number (11802693).

Almost surely, 2^78644945 is an apocalyptic number.

It is an amenable number.

78644945 is a deficient number, since it is larger than the sum of its proper divisors (15776599).

78644945 is a wasteful number, since it uses less digits than its factorization.

78644945 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7939.

The product of its digits is 967680, while the sum is 47.

The square root of 78644945 is about 8868.1985205565. The cubic root of 78644945 is about 428.4402568673.

The spelling of 78644945 in words is "seventy-eight million, six hundred forty-four thousand, nine hundred forty-five".