78142789 has 2 divisors, whose sum is σ = 78142790. Its totient is φ = 78142788.

The previous prime is 78142787. The next prime is 78142817. The reversal of 78142789 is 98724187.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 77968900 + 173889 = 8830^2 + 417^2 .

It is a cyclic number.

It is not a de Polignac number, because 78142789 - 2¹ = 78142787 is a prime.

It is a super-2 number, since 2×78142789² = 12212590945397042, which contains 22 as substring.

Together with 78142787, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (78142783) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39071394 + 39071395.

It is an arithmetic number, because the mean of its divisors is an integer number (39071395).

Almost surely, 2^78142789 is an apocalyptic number.

It is an amenable number.

78142789 is a deficient number, since it is larger than the sum of its proper divisors (1).

78142789 is an equidigital number, since it uses as much as digits as its factorization.

78142789 is an evil number, because the sum of its binary digits is even.

The product of its digits is 225792, while the sum is 46.

The square root of 78142789 is about 8839.8410053575. The cubic root of 78142789 is about 427.5264308864.

The spelling of 78142789 in words is "seventy-eight million, one hundred forty-two thousand, seven hundred eighty-nine".