21355168 has 24 divisors (see below), whose sum is σ = 42759360. Its totient is φ = 10495680.

The previous prime is 21355163. The next prime is 21355199. The reversal of 21355168 is 86155312.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21355163) 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 in 3 ways as a sum of consecutive naturals, for example, 3768 + ... + 7543.

It is an arithmetic number, because the mean of its divisors is an integer number (1781640).

Almost surely, 2^21355168 is an apocalyptic number.

It is an amenable number.

21355168 is an abundant number, since it is smaller than the sum of its proper divisors (21404192).

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

21355168 is a wasteful number, since it uses less digits than its factorization.

21355168 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11380 (or 11372 counting only the distinct ones).

The product of its digits is 7200, while the sum is 31.

The square root of 21355168 is about 4621.1652210238. The cubic root of 21355168 is about 277.4390981791.

The spelling of 21355168 in words is "twenty-one million, three hundred fifty-five thousand, one hundred sixty-eight".