28157249 has 2 divisors, whose sum is σ = 28157250. Its totient is φ = 28157248.

The previous prime is 28157191. The next prime is 28157263. The reversal of 28157249 is 94275182.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 27040000 + 1117249 = 5200^2 + 1057^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-28157249 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (28157279) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14078624 + 14078625.

It is an arithmetic number, because the mean of its divisors is an integer number (14078625).

Almost surely, 2^28157249 is an apocalyptic number.

It is an amenable number.

28157249 is a deficient number, since it is larger than the sum of its proper divisors (1).

28157249 is an equidigital number, since it uses as much as digits as its factorization.

28157249 is an evil number, because the sum of its binary digits is even.

The product of its digits is 40320, while the sum is 38.

The square root of 28157249 is about 5306.3404527037. The cubic root of 28157249 is about 304.2262894150.

The spelling of 28157249 in words is "twenty-eight million, one hundred fifty-seven thousand, two hundred forty-nine".