78391959 has 16 divisors (see below), whose sum is σ = 110769120. Its totient is φ = 49226240.

The previous prime is 78391949. The next prime is 78391979. The reversal of 78391959 is 95919387.

It is a happy number.

It is not a de Polignac number, because 78391959 - 2⁵ = 78391927 is a prime.

It is a super-2 number, since 2×78391959² = 12290598471715362, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78391949) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 7422 + ... + 14555.

It is an arithmetic number, because the mean of its divisors is an integer number (6923070).

Almost surely, 2^78391959 is an apocalyptic number.

78391959 is a deficient number, since it is larger than the sum of its proper divisors (32377161).

78391959 is a wasteful number, since it uses less digits than its factorization.

78391959 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22050.

The product of its digits is 612360, while the sum is 51.

The square root of 78391959 is about 8853.9233676376. The cubic root of 78391959 is about 427.9803594650.

The spelling of 78391959 in words is "seventy-eight million, three hundred ninety-one thousand, nine hundred fifty-nine".