21172608 has 48 divisors (see below), whose sum is σ = 60929700. Its totient is φ = 7057152.

The previous prime is 21172601. The next prime is 21172637. The reversal of 21172608 is 80627112.

It is a tau number, because it is divible by the number of its divisors (48).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21172601) 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 5 ways as a sum of consecutive naturals, for example, 8038 + ... + 10341.

Almost surely, 2^21172608 is an apocalyptic number.

It is an amenable number.

21172608 is an abundant number, since it is smaller than the sum of its proper divisors (39757092).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21172608 is a wasteful number, since it uses less digits than its factorization.

21172608 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18399 (or 18384 counting only the distinct ones).

The product of its (nonzero) digits is 1344, while the sum is 27.

The square root of 21172608 is about 4601.3702307030. The cubic root of 21172608 is about 276.6462487150.

The spelling of 21172608 in words is "twenty-one million, one hundred seventy-two thousand, six hundred eight".