28624421 has 24 divisors (see below), whose sum is σ = 35118720. Its totient is φ = 22825152.

The previous prime is 28624411. The next prime is 28624423. The reversal of 28624421 is 12442682.

It is not a de Polignac number, because 28624421 - 2¹⁸ = 28362277 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (29).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28624423) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 277856 + ... + 277958.

It is an arithmetic number, because the mean of its divisors is an integer number (1463280).

Almost surely, 2^28624421 is an apocalyptic number.

It is an amenable number.

28624421 is a deficient number, since it is larger than the sum of its proper divisors (6494299).

28624421 is a wasteful number, since it uses less digits than its factorization.

28624421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 213 (or 176 counting only the distinct ones).

The product of its digits is 6144, while the sum is 29.

The square root of 28624421 is about 5350.1795296980. The cubic root of 28624421 is about 305.8995961194.

The spelling of 28624421 in words is "twenty-eight million, six hundred twenty-four thousand, four hundred twenty-one".