78788781 has 10 divisors (see below), whose sum is σ = 117696942. Its totient is φ = 52525800.

The previous prime is 78788767. The next prime is 78788789. The reversal of 78788781 is 18788787.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 76842756 + 1946025 = 8766^2 + 1395^2 .

It is not a de Polignac number, because 78788781 - 2¹¹ = 78786733 is a prime.

It is a super-2 number, since 2×78788781² = 12415344022931922, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78788789) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 486270 + ... + 486431.

Almost surely, 2^78788781 is an apocalyptic number.

It is an amenable number.

78788781 is a deficient number, since it is larger than the sum of its proper divisors (38908161).

78788781 is an equidigital number, since it uses as much as digits as its factorization.

78788781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 972713 (or 972704 counting only the distinct ones).

The product of its digits is 1404928, while the sum is 54.

The square root of 78788781 is about 8876.3044675135. The cubic root of 78788781 is about 428.7012933590.

The spelling of 78788781 in words is "seventy-eight million, seven hundred eighty-eight thousand, seven hundred eighty-one".