78238729 has 2 divisors, whose sum is σ = 78238730. Its totient is φ = 78238728.

The previous prime is 78238711. The next prime is 78238739. The reversal of 78238729 is 92783287.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 57032704 + 21206025 = 7552^2 + 4605^2 .

It is a cyclic number.

It is not a de Polignac number, because 78238729 - 2⁹ = 78238217 is a prime.

It is a super-2 number, since 2×78238729² = 12242597431070882, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (78238739) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39119364 + 39119365.

It is an arithmetic number, because the mean of its divisors is an integer number (39119365).

Almost surely, 2^78238729 is an apocalyptic number.

It is an amenable number.

78238729 is a deficient number, since it is larger than the sum of its proper divisors (1).

78238729 is an equidigital number, since it uses as much as digits as its factorization.

78238729 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 338688, while the sum is 46.

The square root of 78238729 is about 8845.2659089481. The cubic root of 78238729 is about 427.7013248702.

The spelling of 78238729 in words is "seventy-eight million, two hundred thirty-eight thousand, seven hundred twenty-nine".