28220402 has 16 divisors (see below), whose sum is σ = 50481792. Its totient is φ = 11568480.

The previous prime is 28220383. The next prime is 28220407. The reversal of 28220402 is 20402282.

It is not an unprimeable number, because it can be changed into a prime (28220407) 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, 43499 + ... + 44142.

It is an arithmetic number, because the mean of its divisors is an integer number (3155112).

Almost surely, 2^28220402 is an apocalyptic number.

28220402 is a deficient number, since it is larger than the sum of its proper divisors (22261390).

28220402 is a wasteful number, since it uses less digits than its factorization.

28220402 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 87673.

The product of its (nonzero) digits is 512, while the sum is 20.

The square root of 28220402 is about 5312.2878310573. The cubic root of 28220402 is about 304.4535660782.

Adding to 28220402 its reverse (20402282), we get a palindrome (48622684).

The spelling of 28220402 in words is "twenty-eight million, two hundred twenty thousand, four hundred two".