28921501 has 4 divisors (see below), whose sum is σ = 33053152. Its totient is φ = 24789852.

The previous prime is 28921489. The next prime is 28921507. The reversal of 28921501 is 10512982.

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 28921501 - 2⁹ = 28920989 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 28921501.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28921507) 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, 2065815 + ... + 2065828.

It is an arithmetic number, because the mean of its divisors is an integer number (8263288).

Almost surely, 2^28921501 is an apocalyptic number.

It is an amenable number.

28921501 is a deficient number, since it is larger than the sum of its proper divisors (4131651).

28921501 is an equidigital number, since it uses as much as digits as its factorization.

28921501 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4131650.

The product of its (nonzero) digits is 1440, while the sum is 28.

The square root of 28921501 is about 5377.8714190654. The cubic root of 28921501 is about 306.9542208049.

The spelling of 28921501 in words is "twenty-eight million, nine hundred twenty-one thousand, five hundred one".