28865921 has 12 divisors (see below), whose sum is σ = 34820352. Its totient is φ = 23437944.

The previous prime is 28865911. The next prime is 28865987. The reversal of 28865921 is 12956882.

It is not a de Polignac number, because 28865921 - 2¹⁴ = 28849537 is a prime.

It is not an unprimeable number, because it can be changed into a prime (28865911) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3185 + ... + 8238.

It is an arithmetic number, because the mean of its divisors is an integer number (2901696).

Almost surely, 2^28865921 is an apocalyptic number.

It is an amenable number.

28865921 is a deficient number, since it is larger than the sum of its proper divisors (5954431).

28865921 is a wasteful number, since it uses less digits than its factorization.

28865921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11468 (or 11449 counting only the distinct ones).

The product of its digits is 69120, while the sum is 41.

The square root of 28865921 is about 5372.7014620208. The cubic root of 28865921 is about 306.7574645810.

The spelling of 28865921 in words is "twenty-eight million, eight hundred sixty-five thousand, nine hundred twenty-one".