28216402 has 4 divisors (see below), whose sum is σ = 42324606. Its totient is φ = 14108200.

The previous prime is 28216399. The next prime is 28216411. The reversal of 28216402 is 20461282.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 20461282 = 2 ⋅10230641.

It can be written as a sum of positive squares in only one way, i.e., 23415921 + 4800481 = 4839^2 + 2191^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7054099 + ... + 7054102.

Almost surely, 2^28216402 is an apocalyptic number.

28216402 is a deficient number, since it is larger than the sum of its proper divisors (14108204).

28216402 is a wasteful number, since it uses less digits than its factorization.

28216402 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14108203.

The product of its (nonzero) digits is 1536, while the sum is 25.

The square root of 28216402 is about 5311.9113320913. The cubic root of 28216402 is about 304.4391808378.

Adding to 28216402 its reverse (20461282), we get a palindrome (48677684).

The spelling of 28216402 in words is "twenty-eight million, two hundred sixteen thousand, four hundred two".