28137709 has 4 divisors (see below), whose sum is σ = 28255680. Its totient is φ = 28019740.

The previous prime is 28137679. The next prime is 28137719. The reversal of 28137709 is 90773182.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 28137709 - 2¹¹ = 28135661 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28137719) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 58627 + ... + 59104.

It is an arithmetic number, because the mean of its divisors is an integer number (7063920).

Almost surely, 2^28137709 is an apocalyptic number.

It is an amenable number.

28137709 is a deficient number, since it is larger than the sum of its proper divisors (117971).

28137709 is a wasteful number, since it uses less digits than its factorization.

28137709 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 117970.

The product of its (nonzero) digits is 21168, while the sum is 37.

The square root of 28137709 is about 5304.4989395795. The cubic root of 28137709 is about 304.1558995209.

The spelling of 28137709 in words is "twenty-eight million, one hundred thirty-seven thousand, seven hundred nine".