78313861 has 2 divisors, whose sum is σ = 78313862. Its totient is φ = 78313860.

The previous prime is 78313853. The next prime is 78313897. The reversal of 78313861 is 16831387.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 53012961 + 25300900 = 7281^2 + 5030^2 .

It is an emirp because it is prime and its reverse (16831387) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 78313861 - 2³ = 78313853 is a prime.

It is a super-2 number, since 2×78313861² = 12266121649454642, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 78313861.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (78313831) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39156930 + 39156931.

It is an arithmetic number, because the mean of its divisors is an integer number (39156931).

Almost surely, 2^78313861 is an apocalyptic number.

It is an amenable number.

78313861 is a deficient number, since it is larger than the sum of its proper divisors (1).

78313861 is an equidigital number, since it uses as much as digits as its factorization.

78313861 is an evil number, because the sum of its binary digits is even.

The product of its digits is 24192, while the sum is 37.

The square root of 78313861 is about 8849.5119074444. The cubic root of 78313861 is about 427.8381870773.

It can be divided in two parts, 7831386 and 1, that added together give a palindrome (7831387).

The spelling of 78313861 in words is "seventy-eight million, three hundred thirteen thousand, eight hundred sixty-one".