78205819 has 16 divisors (see below), whose sum is σ = 84188160. Its totient is φ = 72466240.

The previous prime is 78205811. The next prime is 78205823. The reversal of 78205819 is 91850287.

It is a cyclic number.

It is not a de Polignac number, because 78205819 - 2³ = 78205811 is a prime.

It is a super-2 number, since 2×78205819² = 12232300250921522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (78205811) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 225204 + ... + 225550.

It is an arithmetic number, because the mean of its divisors is an integer number (5261760).

Almost surely, 2^78205819 is an apocalyptic number.

78205819 is a deficient number, since it is larger than the sum of its proper divisors (5982341).

78205819 is a wasteful number, since it uses less digits than its factorization.

78205819 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 650.

The product of its (nonzero) digits is 40320, while the sum is 40.

The square root of 78205819 is about 8843.4053961130. The cubic root of 78205819 is about 427.6413476491.

The spelling of 78205819 in words is "seventy-eight million, two hundred five thousand, eight hundred nineteen".