28221518 has 8 divisors (see below), whose sum is σ = 45588648. Its totient is φ = 13025304.

The previous prime is 28221511. The next prime is 28221533. The reversal of 28221518 is 81512282.

It is a happy number.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28221511) 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, 542696 + ... + 542747.

It is an arithmetic number, because the mean of its divisors is an integer number (5698581).

Almost surely, 2^28221518 is an apocalyptic number.

28221518 is a deficient number, since it is larger than the sum of its proper divisors (17367130).

28221518 is a wasteful number, since it uses less digits than its factorization.

28221518 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1085458.

The product of its digits is 2560, while the sum is 29.

The square root of 28221518 is about 5312.3928695081. The cubic root of 28221518 is about 304.4575793178.

The spelling of 28221518 in words is "twenty-eight million, two hundred twenty-one thousand, five hundred eighteen".