28009651 has 4 divisors (see below), whose sum is σ = 28027432. Its totient is φ = 27991872.

The previous prime is 28009637. The next prime is 28009661. The reversal of 28009651 is 15690082.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 28009651 - 2⁹ = 28009139 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28009661) 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, 6270 + ... + 9763.

It is an arithmetic number, because the mean of its divisors is an integer number (7006858).

Almost surely, 2^28009651 is an apocalyptic number.

28009651 is a deficient number, since it is larger than the sum of its proper divisors (17781).

28009651 is a wasteful number, since it uses less digits than its factorization.

28009651 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17780.

The product of its (nonzero) digits is 4320, while the sum is 31.

The square root of 28009651 is about 5292.4144773440. The cubic root of 28009651 is about 303.6937814182.

The spelling of 28009651 in words is "twenty-eight million, nine thousand, six hundred fifty-one".