28642813 has 4 divisors (see below), whose sum is σ = 28672540. Its totient is φ = 28613088.

The previous prime is 28642811. The next prime is 28642819. The reversal of 28642813 is 31824682.

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 18164644 + 10478169 = 4262^2 + 3237^2 .

It is a cyclic number.

It is not a de Polignac number, because 28642813 - 2¹ = 28642811 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 (28642811) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13368 + ... + 15361.

It is an arithmetic number, because the mean of its divisors is an integer number (7168135).

Almost surely, 2^28642813 is an apocalyptic number.

It is an amenable number.

28642813 is a deficient number, since it is larger than the sum of its proper divisors (29727).

28642813 is an equidigital number, since it uses as much as digits as its factorization.

28642813 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29726.

The product of its digits is 18432, while the sum is 34.

The square root of 28642813 is about 5351.8980745152. The cubic root of 28642813 is about 305.9650984729.

The spelling of 28642813 in words is "twenty-eight million, six hundred forty-two thousand, eight hundred thirteen".