28870389 has 12 divisors (see below), whose sum is σ = 41983500. Its totient is φ = 19116864.

The previous prime is 28870379. The next prime is 28870409. The reversal of 28870389 is 98307882.

It can be written as a sum of positive squares in 2 ways, for example, as 4040100 + 24830289 = 2010^2 + 4983^2 .

It is not a de Polignac number, because 28870389 - 2⁸ = 28870133 is a prime.

It is a super-2 number, since 2×28870389² = 1666998722022642, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28870339) 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, 9424 + ... + 12105.

It is an arithmetic number, because the mean of its divisors is an integer number (3498625).

Almost surely, 2^28870389 is an apocalyptic number.

It is an amenable number.

28870389 is a deficient number, since it is larger than the sum of its proper divisors (13113111).

28870389 is a wasteful number, since it uses less digits than its factorization.

28870389 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21684 (or 21681 counting only the distinct ones).

The product of its (nonzero) digits is 193536, while the sum is 45.

The square root of 28870389 is about 5373.1172516520. The cubic root of 28870389 is about 306.7732908748.

The spelling of 28870389 in words is "twenty-eight million, eight hundred seventy thousand, three hundred eighty-nine".