28432621 has 4 divisors (see below), whose sum is σ = 32494432. Its totient is φ = 24370812.

The previous prime is 28432609. The next prime is 28432637. The reversal of 28432621 is 12623482.

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 a de Polignac number, because none of the positive numbers 2^k-28432621 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 28432621.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28432601) 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, 2030895 + ... + 2030908.

It is an arithmetic number, because the mean of its divisors is an integer number (8123608).

Almost surely, 2^28432621 is an apocalyptic number.

It is an amenable number.

28432621 is a deficient number, since it is larger than the sum of its proper divisors (4061811).

28432621 is an equidigital number, since it uses as much as digits as its factorization.

28432621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4061810.

The product of its digits is 4608, while the sum is 28.

The square root of 28432621 is about 5332.2247702061. The cubic root of 28432621 is about 305.2148302820.

The spelling of 28432621 in words is "twenty-eight million, four hundred thirty-two thousand, six hundred twenty-one".