78878644453521 has 48 divisors (see below), whose sum is σ = 124499353148352. Its totient is φ = 47726165692800.

The previous prime is 78878644453489. The next prime is 78878644453529. The reversal of 78878644453521 is 12535444687887.

78878644453521 is a `hidden beast` number, since 7 + 8 + 8 + 7 + 8 + 6 + 4 + 44 + 53 + 521 = 666.

It is not a de Polignac number, because 78878644453521 - 2⁵ = 78878644453489 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 78878644453521.

It is not an unprimeable number, because it can be changed into a prime (78878644453529) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 175678891 + ... + 176127311.

It is an arithmetic number, because the mean of its divisors is an integer number (2593736523924).

Almost surely, 2^{78878644453521} is an apocalyptic number.

It is an amenable number.

78878644453521 is a deficient number, since it is larger than the sum of its proper divisors (45620708694831).

78878644453521 is a wasteful number, since it uses less digits than its factorization.

78878644453521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 451374 (or 451371 counting only the distinct ones).

The product of its digits is 1445068800, while the sum is 72.

The spelling of 78878644453521 in words is "seventy-eight trillion, eight hundred seventy-eight billion, six hundred forty-four million, four hundred fifty-three thousand, five hundred twenty-one".