28727021 has 4 divisors (see below), whose sum is σ = 28759200. Its totient is φ = 28694844.

The previous prime is 28726981. The next prime is 28727029. The reversal of 28727021 is 12072782.

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-28727021 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28727029) 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, 14711 + ... + 16548.

It is an arithmetic number, because the mean of its divisors is an integer number (7189800).

Almost surely, 2^28727021 is an apocalyptic number.

It is an amenable number.

28727021 is a deficient number, since it is larger than the sum of its proper divisors (32179).

28727021 is an equidigital number, since it uses as much as digits as its factorization.

28727021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32178.

The product of its (nonzero) digits is 3136, while the sum is 29.

The square root of 28727021 is about 5359.7594162425. The cubic root of 28727021 is about 306.2646442532.

The spelling of 28727021 in words is "twenty-eight million, seven hundred twenty-seven thousand, twenty-one".