21226628 has 6 divisors (see below), whose sum is σ = 37146606. Its totient is φ = 10613312.

The previous prime is 21226627. The next prime is 21226633. The reversal of 21226628 is 82662212.

It can be written as a sum of positive squares in only one way, i.e., 16908544 + 4318084 = 4112^2 + 2078^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21226628.

It is not an unprimeable number, because it can be changed into a prime (21226627) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2653325 + ... + 2653332.

It is an arithmetic number, because the mean of its divisors is an integer number (6191101).

Almost surely, 2^21226628 is an apocalyptic number.

It is an amenable number.

21226628 is a deficient number, since it is larger than the sum of its proper divisors (15919978).

21226628 is a wasteful number, since it uses less digits than its factorization.

21226628 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5306661 (or 5306659 counting only the distinct ones).

The product of its digits is 4608, while the sum is 29.

The square root of 21226628 is about 4607.2364818837. The cubic root of 21226628 is about 276.8813282188.

The spelling of 21226628 in words is "twenty-one million, two hundred twenty-six thousand, six hundred twenty-eight".