28609813 has 2 divisors, whose sum is σ = 28609814. Its totient is φ = 28609812.

The previous prime is 28609751. The next prime is 28609829. The reversal of 28609813 is 31890682.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 24581764 + 4028049 = 4958^2 + 2007^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-28609813 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28609873) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14304906 + 14304907.

It is an arithmetic number, because the mean of its divisors is an integer number (14304907).

Almost surely, 2^28609813 is an apocalyptic number.

It is an amenable number.

28609813 is a deficient number, since it is larger than the sum of its proper divisors (1).

28609813 is an equidigital number, since it uses as much as digits as its factorization.

28609813 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 20736, while the sum is 37.

The square root of 28609813 is about 5348.8141676450. The cubic root of 28609813 is about 305.8475503311.

The spelling of 28609813 in words is "twenty-eight million, six hundred nine thousand, eight hundred thirteen".