21106628 has 6 divisors (see below), whose sum is σ = 36936606. Its totient is φ = 10553312.

The previous prime is 21106607. The next prime is 21106643. The reversal of 21106628 is 82660112.

It can be written as a sum of positive squares in only one way, i.e., 21086464 + 20164 = 4592^2 + 142^2 .

It is a super-3 number, since 3×21106628³ (a number of 23 digits) contains 333 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21106597 and 21106606.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2638325 + ... + 2638332.

It is an arithmetic number, because the mean of its divisors is an integer number (6156101).

Almost surely, 2^21106628 is an apocalyptic number.

It is an amenable number.

21106628 is a deficient number, since it is larger than the sum of its proper divisors (15829978).

21106628 is a wasteful number, since it uses less digits than its factorization.

21106628 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5276661 (or 5276659 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 26.

The square root of 21106628 is about 4594.1950328648. The cubic root of 21106628 is about 276.3585796497.

The spelling of 21106628 in words is "twenty-one million, one hundred six thousand, six hundred twenty-eight".