78691311 has 16 divisors (see below), whose sum is σ = 117191520. Its totient is φ = 52185600.

The previous prime is 78691253. The next prime is 78691337. The reversal of 78691311 is 11319687.

It is not a de Polignac number, because 78691311 - 2⁷ = 78691183 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78691381) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2340 + ... + 12761.

It is an arithmetic number, because the mean of its divisors is an integer number (7324470).

Almost surely, 2^78691311 is an apocalyptic number.

78691311 is a deficient number, since it is larger than the sum of its proper divisors (38500209).

78691311 is a wasteful number, since it uses less digits than its factorization.

78691311 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15303 (or 15297 counting only the distinct ones).

The product of its digits is 9072, while the sum is 36.

The square root of 78691311 is about 8870.8123077878. The cubic root of 78691311 is about 428.5244375621.

It can be divided in two parts, 7869 and 1311, that added together give a triangular number (9180 = T₁₃₅).

The spelling of 78691311 in words is "seventy-eight million, six hundred ninety-one thousand, three hundred eleven".