21299228 has 12 divisors (see below), whose sum is σ = 39235560. Its totient is φ = 10089072.

The previous prime is 21299221. The next prime is 21299231. The reversal of 21299228 is 82299212.

It is a super-2 number, since 2×21299228² = 907314226791968, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21299221) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 140051 + ... + 140202.

It is an arithmetic number, because the mean of its divisors is an integer number (3269630).

Almost surely, 2^21299228 is an apocalyptic number.

It is an amenable number.

21299228 is a deficient number, since it is larger than the sum of its proper divisors (17936332).

21299228 is a wasteful number, since it uses less digits than its factorization.

21299228 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 280276 (or 280274 counting only the distinct ones).

The product of its digits is 10368, while the sum is 35.

The square root of 21299228 is about 4615.1086661096. The cubic root of 21299228 is about 277.1966351769.

The spelling of 21299228 in words is "twenty-one million, two hundred ninety-nine thousand, two hundred twenty-eight".