802780813 has 4 divisors (see below), whose sum is σ = 830462940. Its totient is φ = 775098688.

The previous prime is 802780787. The next prime is 802780841. The reversal of 802780813 is 318087208.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 143472484 + 659308329 = 11978^2 + 25677^2 .

It is a cyclic number.

It is not a de Polignac number, because 802780813 - 2¹⁷ = 802649741 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (802780513) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13841020 + ... + 13841077.

It is an arithmetic number, because the mean of its divisors is an integer number (207615735).

Almost surely, 2^802780813 is an apocalyptic number.

It is an amenable number.

802780813 is a deficient number, since it is larger than the sum of its proper divisors (27682127).

802780813 is a wasteful number, since it uses less digits than its factorization.

802780813 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27682126.

The product of its (nonzero) digits is 21504, while the sum is 37.

The square root of 802780813 is about 28333.3868960278. The cubic root of 802780813 is about 929.3921387184.

The spelling of 802780813 in words is "eight hundred two million, seven hundred eighty thousand, eight hundred thirteen".