78161789 has 2 divisors, whose sum is σ = 78161790. Its totient is φ = 78161788.

The previous prime is 78161737. The next prime is 78161807. The reversal of 78161789 is 98716187.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 48372025 + 29789764 = 6955^2 + 5458^2 .

It is a cyclic number.

It is not a de Polignac number, because 78161789 - 2¹⁶ = 78096253 is a prime.

It is a super-3 number, since 3×78161789³ (a number of 25 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (78161089) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39080894 + 39080895.

It is an arithmetic number, because the mean of its divisors is an integer number (39080895).

Almost surely, 2^78161789 is an apocalyptic number.

It is an amenable number.

78161789 is a deficient number, since it is larger than the sum of its proper divisors (1).

78161789 is an equidigital number, since it uses as much as digits as its factorization.

78161789 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 169344, while the sum is 47.

The square root of 78161789 is about 8840.9156200023. The cubic root of 78161789 is about 427.5610783312.

It can be divided in two parts, 7816178 and 9, that added together give a palindrome (7816187).

The spelling of 78161789 in words is "seventy-eight million, one hundred sixty-one thousand, seven hundred eighty-nine".