28537813 has 4 divisors (see below), whose sum is σ = 29005708. Its totient is φ = 28069920.

The previous prime is 28537801. The next prime is 28537823. The reversal of 28537813 is 31873582.

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 10712529 + 17825284 = 3273^2 + 4222^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-28537813 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 (28537823) 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, 233856 + ... + 233977.

It is an arithmetic number, because the mean of its divisors is an integer number (7251427).

Almost surely, 2^28537813 is an apocalyptic number.

It is an amenable number.

28537813 is a deficient number, since it is larger than the sum of its proper divisors (467895).

28537813 is an equidigital number, since it uses as much as digits as its factorization.

28537813 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 467894.

The product of its digits is 40320, while the sum is 37.

The square root of 28537813 is about 5342.0794640290. The cubic root of 28537813 is about 305.5907675466.

The spelling of 28537813 in words is "twenty-eight million, five hundred thirty-seven thousand, eight hundred thirteen".