78138545 has 16 divisors (see below), whose sum is σ = 104509440. Its totient is φ = 55736064.

The previous prime is 78138539. The next prime is 78138547. The reversal of 78138545 is 54583187.

It is a de Polignac number, because none of the positive numbers 2^k-78138545 is a prime.

It is a super-2 number, since 2×78138545² = 12211264429434050, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (78138547) 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 15 ways as a sum of consecutive naturals, for example, 22577 + ... + 25806.

It is an arithmetic number, because the mean of its divisors is an integer number (6531840).

Almost surely, 2^78138545 is an apocalyptic number.

It is an amenable number.

78138545 is a deficient number, since it is larger than the sum of its proper divisors (26370895).

78138545 is a wasteful number, since it uses less digits than its factorization.

78138545 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 48424.

The product of its digits is 134400, while the sum is 41.

The square root of 78138545 is about 8839.6009525317. The cubic root of 78138545 is about 427.5186909740.

The spelling of 78138545 in words is "seventy-eight million, one hundred thirty-eight thousand, five hundred forty-five".