78966121 has 4 divisors (see below), whose sum is σ = 85040452. Its totient is φ = 72891792.

The previous prime is 78966113. The next prime is 78966127. The reversal of 78966121 is 12166987.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12166987 = 7 ⋅1738141.

It can be written as a sum of positive squares in 2 ways, for example, as 30858025 + 48108096 = 5555^2 + 6936^2 .

It is a cyclic number.

It is not a de Polignac number, because 78966121 - 2³ = 78966113 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (78966127) 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, 3037146 + ... + 3037171.

It is an arithmetic number, because the mean of its divisors is an integer number (21260113).

Almost surely, 2^78966121 is an apocalyptic number.

It is an amenable number.

78966121 is a deficient number, since it is larger than the sum of its proper divisors (6074331).

78966121 is a wasteful number, since it uses less digits than its factorization.

78966121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6074330.

The product of its digits is 36288, while the sum is 40.

The square root of 78966121 is about 8886.2883702927. The cubic root of 78966121 is about 429.0226966401.

The spelling of 78966121 in words is "seventy-eight million, nine hundred sixty-six thousand, one hundred twenty-one".