78387389 has 2 divisors, whose sum is σ = 78387390. Its totient is φ = 78387388.

The previous prime is 78387383. The next prime is 78387457. The reversal of 78387389 is 98378387.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 75394489 + 2992900 = 8683^2 + 1730^2 .

It is a cyclic number.

It is not a de Polignac number, because 78387389 - 2¹⁶ = 78321853 is a prime.

It is a super-2 number, since 2×78387389² = 12289165508474642, 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 78387389.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (78387383) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39193694 + 39193695.

It is an arithmetic number, because the mean of its divisors is an integer number (39193695).

Almost surely, 2^78387389 is an apocalyptic number.

It is an amenable number.

78387389 is a deficient number, since it is larger than the sum of its proper divisors (1).

78387389 is an equidigital number, since it uses as much as digits as its factorization.

78387389 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2032128, while the sum is 53.

The square root of 78387389 is about 8853.6652861964. The cubic root of 78387389 is about 427.9720426755.

The spelling of 78387389 in words is "seventy-eight million, three hundred eighty-seven thousand, three hundred eighty-nine".