78390887 has 4 divisors (see below), whose sum is σ = 79495056. Its totient is φ = 77286720.

The previous prime is 78390883. The next prime is 78390889. The reversal of 78390887 is 78809387.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 78809387 = 137 ⋅575251.

It is a cyclic number.

It is not a de Polignac number, because 78390887 - 2² = 78390883 is a prime.

It is a super-2 number, since 2×78390887² = 12290262329293538, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78390883) 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 3 ways as a sum of consecutive naturals, for example, 551978 + ... + 552119.

It is an arithmetic number, because the mean of its divisors is an integer number (19873764).

Almost surely, 2^78390887 is an apocalyptic number.

78390887 is a deficient number, since it is larger than the sum of its proper divisors (1104169).

78390887 is a wasteful number, since it uses less digits than its factorization.

78390887 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1104168.

The product of its (nonzero) digits is 677376, while the sum is 50.

The square root of 78390887 is about 8853.8628292966. The cubic root of 78390887 is about 427.9784085972.

The spelling of 78390887 in words is "seventy-eight million, three hundred ninety thousand, eight hundred eighty-seven".