78370781 has 2 divisors, whose sum is σ = 78370782. Its totient is φ = 78370780.

The previous prime is 78370753. The next prime is 78370807. The reversal of 78370781 is 18707387.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 76282756 + 2088025 = 8734^2 + 1445^2 .

It is a cyclic number.

It is not a de Polignac number, because 78370781 - 2¹⁰ = 78369757 is a prime.

It is a super-2 number, since 2×78370781² = 12283958629099922, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (78370711) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39185390 + 39185391.

It is an arithmetic number, because the mean of its divisors is an integer number (39185391).

Almost surely, 2^78370781 is an apocalyptic number.

It is an amenable number.

78370781 is a deficient number, since it is larger than the sum of its proper divisors (1).

78370781 is an equidigital number, since it uses as much as digits as its factorization.

78370781 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 65856, while the sum is 41.

The square root of 78370781 is about 8852.7273198715. The cubic root of 78370781 is about 427.9418156122.

The spelling of 78370781 in words is "seventy-eight million, three hundred seventy thousand, seven hundred eighty-one".