78389555 has 4 divisors (see below), whose sum is σ = 94067472. Its totient is φ = 62711640.

The previous prime is 78389551. The next prime is 78389557. The reversal of 78389555 is 55598387.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 55598387 = 13 ⋅4276799.

It is not a de Polignac number, because 78389555 - 2² = 78389551 is a prime.

It is a super-2 number, since 2×78389555² = 12289844666196050, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (78389551) 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 in 3 ways as a sum of consecutive naturals, for example, 7838951 + ... + 7838960.

It is an arithmetic number, because the mean of its divisors is an integer number (23516868).

Almost surely, 2^78389555 is an apocalyptic number.

78389555 is a deficient number, since it is larger than the sum of its proper divisors (15677917).

78389555 is a wasteful number, since it uses less digits than its factorization.

78389555 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15677916.

The product of its digits is 1512000, while the sum is 50.

The square root of 78389555 is about 8853.7876075723. The cubic root of 78389555 is about 427.9759845465.

The spelling of 78389555 in words is "seventy-eight million, three hundred eighty-nine thousand, five hundred fifty-five".