28727421 has 16 divisors (see below), whose sum is σ = 39936000. Its totient is φ = 18347760.

The previous prime is 28727417. The next prime is 28727459. The reversal of 28727421 is 12472782.

It is not a de Polignac number, because 28727421 - 2² = 28727417 is a prime.

It is a super-2 number, since 2×28727421² = 1650529434622482, which contains 22 as substring.

Its product of digits (12544) is a multiple of the sum of its prime divisors (3136).

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28725421) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8080 + ... + 11078.

It is an arithmetic number, because the mean of its divisors is an integer number (2496000).

Almost surely, 2^28727421 is an apocalyptic number.

It is an amenable number.

28727421 is a deficient number, since it is larger than the sum of its proper divisors (11208579).

28727421 is a wasteful number, since it uses less digits than its factorization.

28727421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3136.

The product of its digits is 12544, while the sum is 33.

The square root of 28727421 is about 5359.7967312203. The cubic root of 28727421 is about 306.2660657406.

The spelling of 28727421 in words is "twenty-eight million, seven hundred twenty-seven thousand, four hundred twenty-one".