28253721 has 8 divisors (see below), whose sum is σ = 38473344. Its totient is φ = 18434960.

The previous prime is 28253713. The next prime is 28253747. The reversal of 28253721 is 12735282.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 28253721 - 2³ = 28253713 is a prime.

It is not an unprimeable number, because it can be changed into a prime (28253521) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 100050 + ... + 100331.

It is an arithmetic number, because the mean of its divisors is an integer number (4809168).

Almost surely, 2^28253721 is an apocalyptic number.

It is an amenable number.

28253721 is a deficient number, since it is larger than the sum of its proper divisors (10219623).

28253721 is a wasteful number, since it uses less digits than its factorization.

28253721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 200431.

The product of its digits is 6720, while the sum is 30.

The square root of 28253721 is about 5315.4229370766. The cubic root of 28253721 is about 304.5733387485.

The spelling of 28253721 in words is "twenty-eight million, two hundred fifty-three thousand, seven hundred twenty-one".