78780605685551 has 24 divisors (see below), whose sum is σ = 99200258183040. Its totient is φ = 61240975163280.

The previous prime is 78780605685539. The next prime is 78780605685599. The reversal of 78780605685551 is 15558650608787.

It is not a de Polignac number, because 78780605685551 - 2³⁸ = 78505727778607 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78780605685751) 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 23 ways as a sum of consecutive naturals, for example, 110637161 + ... + 111346946.

It is an arithmetic number, because the mean of its divisors is an integer number (4133344090960).

Almost surely, 2^{78780605685551} is an apocalyptic number.

78780605685551 is a deficient number, since it is larger than the sum of its proper divisors (20419652497489).

78780605685551 is a wasteful number, since it uses less digits than its factorization.

78780605685551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 221984555 (or 221984544 counting only the distinct ones).

The product of its (nonzero) digits is 564480000, while the sum is 71.

The spelling of 78780605685551 in words is "seventy-eight trillion, seven hundred eighty billion, six hundred five million, six hundred eighty-five thousand, five hundred fifty-one".