28810321 has 2 divisors, whose sum is σ = 28810322. Its totient is φ = 28810320.

The previous prime is 28810319. The next prime is 28810333. The reversal of 28810321 is 12301882.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21520321 + 7290000 = 4639^2 + 2700^2 .

It is a cyclic number.

It is not a de Polignac number, because 28810321 - 2¹ = 28810319 is a prime.

It is a super-2 number, since 2×28810321² = 1660069192246082, which contains 22 as substring.

Together with 28810319, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (28810381) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14405160 + 14405161.

It is an arithmetic number, because the mean of its divisors is an integer number (14405161).

Almost surely, 2^28810321 is an apocalyptic number.

It is an amenable number.

28810321 is a deficient number, since it is larger than the sum of its proper divisors (1).

28810321 is an equidigital number, since it uses as much as digits as its factorization.

28810321 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 768, while the sum is 25.

The square root of 28810321 is about 5367.5246622629. The cubic root of 28810321 is about 306.5603846938.

It can be divided in two parts, 288 and 10321, that added together give a square (10609 = 103²).

The spelling of 28810321 in words is "twenty-eight million, eight hundred ten thousand, three hundred twenty-one".