78669889 has 2 divisors, whose sum is σ = 78669890. Its totient is φ = 78669888.

The previous prime is 78669853. The next prime is 78669893. The reversal of 78669889 is 98896687.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 77000625 + 1669264 = 8775^2 + 1292^2 .

It is an emirp because it is prime and its reverse (98896687) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 78669889 - 2¹³ = 78661697 is a prime.

It is not a weakly prime, because it can be changed into another prime (78669839) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39334944 + 39334945.

It is an arithmetic number, because the mean of its divisors is an integer number (39334945).

Almost surely, 2^78669889 is an apocalyptic number.

It is an amenable number.

78669889 is a deficient number, since it is larger than the sum of its proper divisors (1).

78669889 is an equidigital number, since it uses as much as digits as its factorization.

78669889 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 10450944, while the sum is 61.

The square root of 78669889 is about 8869.6047826270. The cubic root of 78669889 is about 428.4855485433.

The spelling of 78669889 in words is "seventy-eight million, six hundred sixty-nine thousand, eight hundred eighty-nine".