78000121 has 2 divisors, whose sum is σ = 78000122. Its totient is φ = 78000120.

The previous prime is 78000113. The next prime is 78000133. The reversal of 78000121 is 12100087.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 51322896 + 26677225 = 7164^2 + 5165^2 .

It is an emirp because it is prime and its reverse (12100087) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 78000121 - 2³ = 78000113 is a prime.

It is not a weakly prime, because it can be changed into another prime (78000101) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39000060 + 39000061.

It is an arithmetic number, because the mean of its divisors is an integer number (39000061).

Almost surely, 2^78000121 is an apocalyptic number.

It is an amenable number.

78000121 is a deficient number, since it is larger than the sum of its proper divisors (1).

78000121 is an equidigital number, since it uses as much as digits as its factorization.

78000121 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 112, while the sum is 19.

The square root of 78000121 is about 8831.7677166012. The cubic root of 78000121 is about 427.2660891063.

The spelling of 78000121 in words is "seventy-eight million, one hundred twenty-one", and thus it is an aban number.