21122008 has 8 divisors (see below), whose sum is σ = 39603780. Its totient is φ = 10561000.

The previous prime is 21121999. The next prime is 21122009. The reversal of 21122008 is 80022112.

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

It is a super-2 number, since 2×21122008² = 892278443904128, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21121982 and 21122000.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21122009) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1320118 + ... + 1320133.

Almost surely, 2^21122008 is an apocalyptic number.

It is an amenable number.

21122008 is a deficient number, since it is larger than the sum of its proper divisors (18481772).

21122008 is a wasteful number, since it uses less digits than its factorization.

21122008 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2640257 (or 2640253 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 16.

The square root of 21122008 is about 4595.8685794962. The cubic root of 21122008 is about 276.4256891058.

The spelling of 21122008 in words is "twenty-one million, one hundred twenty-two thousand, eight".