77840285 has 4 divisors (see below), whose sum is σ = 93408348. Its totient is φ = 62272224.

The previous prime is 77840239. The next prime is 77840299. The reversal of 77840285 is 58204877.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 58204877 = 71 ⋅819787.

It can be written as a sum of positive squares in 2 ways, for example, as 38477209 + 39363076 = 6203^2 + 6274^2 .

It is a cyclic number.

It is not a de Polignac number, because 77840285 - 2⁸ = 77840029 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7784024 + ... + 7784033.

It is an arithmetic number, because the mean of its divisors is an integer number (23352087).

Almost surely, 2^77840285 is an apocalyptic number.

It is an amenable number.

77840285 is a deficient number, since it is larger than the sum of its proper divisors (15568063).

77840285 is a wasteful number, since it uses less digits than its factorization.

77840285 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15568062.

The product of its (nonzero) digits is 125440, while the sum is 41.

The square root of 77840285 is about 8822.7141515522. The cubic root of 77840285 is about 426.9740416808.

It can be divided in two parts, 77840 and 285, that added together give a 7-th power (78125 = 5⁷).

The spelling of 77840285 in words is "seventy-seven million, eight hundred forty thousand, two hundred eighty-five".