28902805 has 16 divisors (see below), whose sum is σ = 36869040. Its totient is φ = 21676032.

The previous prime is 28902793. The next prime is 28902829. The reversal of 28902805 is 50820982.

28902805 = 3801² + 3802².

It can be written as a sum of positive squares in 8 ways, for example, as 579121 + 28323684 = 761^2 + 5322^2 .

It is a 7-Lehmer number, since φ(28902805) divides (28902805-1)⁷.

It is a cyclic number.

It is not a de Polignac number, because 28902805 - 2⁷ = 28902677 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 28141 + ... + 29149.

It is an arithmetic number, because the mean of its divisors is an integer number (2304315).

Almost surely, 2^28902805 is an apocalyptic number.

28902805 is the 3802-nd centered square number.

It is an amenable number.

28902805 is a deficient number, since it is larger than the sum of its proper divisors (7966235).

28902805 is a wasteful number, since it uses less digits than its factorization.

28902805 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1368.

The product of its (nonzero) digits is 11520, while the sum is 34.

The square root of 28902805 is about 5376.1329038631. The cubic root of 28902805 is about 306.8880641054. Note that the first 3 decimals are identical.

The spelling of 28902805 in words is "twenty-eight million, nine hundred two thousand, eight hundred five".