78002161 has 2 divisors, whose sum is σ = 78002162. Its totient is φ = 78002160.

The previous prime is 78002149. The next prime is 78002207. The reversal of 78002161 is 16120087.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 74649600 + 3352561 = 8640^2 + 1831^2 .

It is a cyclic number.

It is not a de Polignac number, because 78002161 - 2¹¹ = 78000113 is a prime.

It is not a weakly prime, because it can be changed into another prime (78002461) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39001080 + 39001081.

It is an arithmetic number, because the mean of its divisors is an integer number (39001081).

Almost surely, 2^78002161 is an apocalyptic number.

It is an amenable number.

78002161 is a deficient number, since it is larger than the sum of its proper divisors (1).

78002161 is an equidigital number, since it uses as much as digits as its factorization.

78002161 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 672, while the sum is 25.

The square root of 78002161 is about 8831.8832080140. The cubic root of 78002161 is about 427.2698139519.

The spelling of 78002161 in words is "seventy-eight million, two thousand, one hundred sixty-one".