28137609 has 12 divisors (see below), whose sum is σ = 41588976. Its totient is φ = 18321912.

The previous prime is 28137589. The next prime is 28137661. The reversal of 28137609 is 90673182.

28137609 is a `hidden beast` number, since 281 + 376 + 0 + 9 = 666.

It is not a de Polignac number, because 28137609 - 2⁷ = 28137481 is a prime.

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (28137679) 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, 35967 + ... + 36740.

It is an arithmetic number, because the mean of its divisors is an integer number (3465748).

Almost surely, 2^28137609 is an apocalyptic number.

It is an amenable number.

28137609 is a deficient number, since it is larger than the sum of its proper divisors (13451367).

28137609 is a wasteful number, since it uses less digits than its factorization.

28137609 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 72756 (or 72753 counting only the distinct ones).

The product of its (nonzero) digits is 18144, while the sum is 36.

The square root of 28137609 is about 5304.4895136101. The cubic root of 28137609 is about 304.1555392022.

The spelling of 28137609 in words is "twenty-eight million, one hundred thirty-seven thousand, six hundred nine".