78850861 has 2 divisors, whose sum is σ = 78850862. Its totient is φ = 78850860.

The previous prime is 78850859. The next prime is 78850873. The reversal of 78850861 is 16805887.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 50495236 + 28355625 = 7106^2 + 5325^2 .

It is a cyclic number.

It is not a de Polignac number, because 78850861 - 2¹ = 78850859 is a prime.

Together with 78850859, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (78850661) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39425430 + 39425431.

It is an arithmetic number, because the mean of its divisors is an integer number (39425431).

Almost surely, 2^78850861 is an apocalyptic number.

It is an amenable number.

78850861 is a deficient number, since it is larger than the sum of its proper divisors (1).

78850861 is an equidigital number, since it uses as much as digits as its factorization.

78850861 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 107520, while the sum is 43.

The square root of 78850861 is about 8879.8007297461. The cubic root of 78850861 is about 428.8138592560.

The spelling of 78850861 in words is "seventy-eight million, eight hundred fifty thousand, eight hundred sixty-one".