7728813 has 6 divisors (see below), whose sum is σ = 11163854. Its totient is φ = 5152536.

The previous prime is 7728803. The next prime is 7728841. The reversal of 7728813 is 3188277.

It can be written as a sum of positive squares in only one way, i.e., 5774409 + 1954404 = 2403^2 + 1398^2 .

It is not a de Polignac number, because 7728813 - 2⁴ = 7728797 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 (7728803) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 429370 + ... + 429387.

Almost surely, 2^7728813 is an apocalyptic number.

It is an amenable number.

7728813 is a deficient number, since it is larger than the sum of its proper divisors (3435041).

7728813 is a wasteful number, since it uses less digits than its factorization.

7728813 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 858763 (or 858760 counting only the distinct ones).

The product of its digits is 18816, while the sum is 36.

The square root of 7728813 is about 2780.0742795832. The cubic root of 7728813 is about 197.7140807399.

The spelling of 7728813 in words is "seven million, seven hundred twenty-eight thousand, eight hundred thirteen".