28219257 has 18 divisors (see below), whose sum is σ = 44805306. Its totient is φ = 17101920.

The previous prime is 28219211. The next prime is 28219277. The reversal of 28219257 is 75291282.

It can be written as a sum of positive squares in only one way, i.e., 25160256 + 3059001 = 5016^2 + 1749^2 .

It is not a de Polignac number, because 28219257 - 2¹¹ = 28217209 is a prime.

It is not an unprimeable number, because it can be changed into a prime (28219277) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 11868 + ... + 14045.

Almost surely, 2^28219257 is an apocalyptic number.

It is an amenable number.

28219257 is a deficient number, since it is larger than the sum of its proper divisors (16586049).

28219257 is a wasteful number, since it uses less digits than its factorization.

28219257 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25941 (or 25927 counting only the distinct ones).

The product of its digits is 20160, while the sum is 36.

The square root of 28219257 is about 5312.1800609543. The cubic root of 28219257 is about 304.4494484420.

The spelling of 28219257 in words is "twenty-eight million, two hundred nineteen thousand, two hundred fifty-seven".