78013121 has 4 divisors (see below), whose sum is σ = 78316932. Its totient is φ = 77709312.

The previous prime is 78013097. The next prime is 78013147. The reversal of 78013121 is 12131087.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12131087 = 67 ⋅181061.

It can be written as a sum of positive squares in 2 ways, for example, as 75881521 + 2131600 = 8711^2 + 1460^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-78013121 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (78013151) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 151520 + ... + 152033.

It is an arithmetic number, because the mean of its divisors is an integer number (19579233).

Almost surely, 2^78013121 is an apocalyptic number.

It is an amenable number.

78013121 is a deficient number, since it is larger than the sum of its proper divisors (303811).

78013121 is a wasteful number, since it uses less digits than its factorization.

78013121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 303810.

The product of its (nonzero) digits is 336, while the sum is 23.

The square root of 78013121 is about 8832.5036654394. The cubic root of 78013121 is about 427.2898247558.

The spelling of 78013121 in words is "seventy-eight million, thirteen thousand, one hundred twenty-one".