78073889 has 2 divisors, whose sum is σ = 78073890. Its totient is φ = 78073888.

The previous prime is 78073871. The next prime is 78073901. The reversal of 78073889 is 98837087.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 77704225 + 369664 = 8815^2 + 608^2 .

It is a cyclic number.

It is not a de Polignac number, because 78073889 - 2²⁰ = 77025313 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (78073859) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39036944 + 39036945.

It is an arithmetic number, because the mean of its divisors is an integer number (39036945).

Almost surely, 2^78073889 is an apocalyptic number.

It is an amenable number.

78073889 is a deficient number, since it is larger than the sum of its proper divisors (1).

78073889 is an equidigital number, since it uses as much as digits as its factorization.

78073889 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 677376, while the sum is 50.

The square root of 78073889 is about 8835.9430170186. The cubic root of 78073889 is about 427.4007411792.

The spelling of 78073889 in words is "seventy-eight million, seventy-three thousand, eight hundred eighty-nine".