78061128121 has 4 divisors (see below), whose sum is σ = 78072559092. Its totient is φ = 78049697152.

The previous prime is 78061128107. The next prime is 78061128127. The reversal of 78061128121 is 12182116087.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12182116087 = 2063 ⋅5905049.

It can be written as a sum of positive squares in 2 ways, for example, as 30972128121 + 47089000000 = 175989^2 + 217000^2 .

It is a cyclic number.

It is not a de Polignac number, because 78061128121 - 2¹⁹ = 78060603833 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (78061128127) 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, 5705236 + ... + 5718901.

It is an arithmetic number, because the mean of its divisors is an integer number (19518139773).

Almost surely, 2^78061128121 is an apocalyptic number.

It is an amenable number.

78061128121 is a deficient number, since it is larger than the sum of its proper divisors (11430971).

78061128121 is a wasteful number, since it uses less digits than its factorization.

78061128121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11430970.

The product of its (nonzero) digits is 10752, while the sum is 37.

The spelling of 78061128121 in words is "seventy-eight billion, sixty-one million, one hundred twenty-eight thousand, one hundred twenty-one".