78887865 has 32 divisors (see below), whose sum is σ = 144587520. Its totient is φ = 35979264.

The previous prime is 78887863. The next prime is 78887881. The reversal of 78887865 is 56878887.

It is not a de Polignac number, because 78887865 - 2¹ = 78887863 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (78887863) 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 31 ways as a sum of consecutive naturals, for example, 80257 + ... + 81233.

It is an arithmetic number, because the mean of its divisors is an integer number (4518360).

Almost surely, 2^78887865 is an apocalyptic number.

It is an amenable number.

78887865 is a deficient number, since it is larger than the sum of its proper divisors (65699655).

78887865 is a wasteful number, since it uses less digits than its factorization.

78887865 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1761.

The product of its digits is 6021120, while the sum is 57.

The square root of 78887865 is about 8881.8840906645. The cubic root of 78887865 is about 428.8809282615.

It can be divided in two parts, 7888 and 7865, that added together give a triangular number (15753 = T₁₇₇).

The spelling of 78887865 in words is "seventy-eight million, eight hundred eighty-seven thousand, eight hundred sixty-five".