28121507 has 8 divisors (see below), whose sum is σ = 28459200. Its totient is φ = 27786024.

The previous prime is 28121497. The next prime is 28121521. The reversal of 28121507 is 70512182.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 28121507 - 2⁴ = 28121491 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28121207) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 42344 + ... + 43002.

It is an arithmetic number, because the mean of its divisors is an integer number (3557400).

Almost surely, 2^28121507 is an apocalyptic number.

28121507 is a deficient number, since it is larger than the sum of its proper divisors (337693).

28121507 is a wasteful number, since it uses less digits than its factorization.

28121507 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1105.

The product of its (nonzero) digits is 1120, while the sum is 26.

The square root of 28121507 is about 5302.9715254751. The cubic root of 28121507 is about 304.0975095498.

Adding to 28121507 its reverse (70512182), we get a palindrome (98633689).

The spelling of 28121507 in words is "twenty-eight million, one hundred twenty-one thousand, five hundred seven".