78972389 has 2 divisors, whose sum is σ = 78972390. Its totient is φ = 78972388.

The previous prime is 78972371. The next prime is 78972391. The reversal of 78972389 is 98327987.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 54390625 + 24581764 = 7375^2 + 4958^2 .

It is a cyclic number.

It is not a de Polignac number, because 78972389 - 2¹⁶ = 78906853 is a prime.

Together with 78972391, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 78972389.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (78972329) 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, 39486194 + 39486195.

It is an arithmetic number, because the mean of its divisors is an integer number (39486195).

Almost surely, 2^78972389 is an apocalyptic number.

It is an amenable number.

78972389 is a deficient number, since it is larger than the sum of its proper divisors (1).

78972389 is an equidigital number, since it uses as much as digits as its factorization.

78972389 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1524096, while the sum is 53.

The square root of 78972389 is about 8886.6410414734. The cubic root of 78972389 is about 429.0340476814.

The spelling of 78972389 in words is "seventy-eight million, nine hundred seventy-two thousand, three hundred eighty-nine".