78827781 has 8 divisors (see below), whose sum is σ = 105188224. Its totient is φ = 52509600.

The previous prime is 78827779. The next prime is 78827803. The reversal of 78827781 is 18772887.

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

It is not a de Polignac number, because 78827781 - 2¹ = 78827779 is a prime.

It is a super-2 number, since 2×78827781² = 12427638114767922, which contains 22 as substring.

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 78827781.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78827731) 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 7 ways as a sum of consecutive naturals, for example, 5920 + ... + 13881.

It is an arithmetic number, because the mean of its divisors is an integer number (13148528).

Almost surely, 2^78827781 is an apocalyptic number.

It is an amenable number.

78827781 is a deficient number, since it is larger than the sum of its proper divisors (26360443).

78827781 is a wasteful number, since it uses less digits than its factorization.

78827781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21131.

The product of its digits is 351232, while the sum is 48.

The square root of 78827781 is about 8878.5010559215. The cubic root of 78827781 is about 428.7720165945.

The spelling of 78827781 in words is "seventy-eight million, eight hundred twenty-seven thousand, seven hundred eighty-one".