21106408 has 8 divisors (see below), whose sum is σ = 39574530. Its totient is φ = 10553200.

The previous prime is 21106399. The next prime is 21106411. The reversal of 21106408 is 80460112.

It can be written as a sum of positive squares in only one way, i.e., 19027044 + 2079364 = 4362^2 + 1442^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1319143 + ... + 1319158.

Almost surely, 2^21106408 is an apocalyptic number.

It is an amenable number.

21106408 is a deficient number, since it is larger than the sum of its proper divisors (18468122).

21106408 is a wasteful number, since it uses less digits than its factorization.

21106408 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2638307 (or 2638303 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 22.

The square root of 21106408 is about 4594.1710895438. The cubic root of 21106408 is about 276.3576194600.

The spelling of 21106408 in words is "twenty-one million, one hundred six thousand, four hundred eight".