78656781 has 16 divisors (see below), whose sum is σ = 120472704. Its totient is φ = 44716224.

The previous prime is 78656771. The next prime is 78656801. The reversal of 78656781 is 18765687.

It is not a de Polignac number, because 78656781 - 2⁵ = 78656749 is a prime.

It is a super-2 number, since 2×78656781² = 12373778394563922, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 78656781.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78656731) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5370 + ... + 13643.

It is an arithmetic number, because the mean of its divisors is an integer number (7529544).

Almost surely, 2^78656781 is an apocalyptic number.

It is an amenable number.

78656781 is a deficient number, since it is larger than the sum of its proper divisors (41815923).

78656781 is a wasteful number, since it uses less digits than its factorization.

78656781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19220.

The product of its digits is 564480, while the sum is 48.

The square root of 78656781 is about 8868.8658237680. The cubic root of 78656781 is about 428.4617490921.

The spelling of 78656781 in words is "seventy-eight million, six hundred fifty-six thousand, seven hundred eighty-one".