78868121 has 4 divisors (see below), whose sum is σ = 78886500. Its totient is φ = 78849744.

The previous prime is 78868109. The next prime is 78868147. The reversal of 78868121 is 12186887.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12186887 = 659 ⋅18493.

It can be written as a sum of positive squares in 2 ways, for example, as 63027721 + 15840400 = 7939^2 + 3980^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-78868121 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (78868721) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1055 + ... + 12603.

It is an arithmetic number, because the mean of its divisors is an integer number (19721625).

Almost surely, 2^78868121 is an apocalyptic number.

It is an amenable number.

78868121 is a deficient number, since it is larger than the sum of its proper divisors (18379).

78868121 is a wasteful number, since it uses less digits than its factorization.

78868121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18378.

The product of its digits is 43008, while the sum is 41.

The square root of 78868121 is about 8880.7725452238. The cubic root of 78868121 is about 428.8451452692.

The spelling of 78868121 in words is "seventy-eight million, eight hundred sixty-eight thousand, one hundred twenty-one".