28612221 has 8 divisors (see below), whose sum is σ = 41617824. Its totient is φ = 17340720.

The previous prime is 28612217. The next prime is 28612229. The reversal of 28612221 is 12221682.

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

It is not a de Polignac number, because 28612221 - 2² = 28612217 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 28612191 and 28612200.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28612229) 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, 433486 + ... + 433551.

It is an arithmetic number, because the mean of its divisors is an integer number (5202228).

Almost surely, 2^28612221 is an apocalyptic number.

It is an amenable number.

28612221 is a deficient number, since it is larger than the sum of its proper divisors (13005603).

28612221 is a wasteful number, since it uses less digits than its factorization.

28612221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 867051.

The product of its digits is 768, while the sum is 24.

The square root of 28612221 is about 5349.0392595306. The cubic root of 28612221 is about 305.8561308397.

The spelling of 28612221 in words is "twenty-eight million, six hundred twelve thousand, two hundred twenty-one".