21555133 has 8 divisors (see below), whose sum is σ = 22999680. Its totient is φ = 20130240.

The previous prime is 21555113. The next prime is 21555179. The reversal of 21555133 is 33155512.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21555133 - 2¹⁷ = 21424061 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21555098 and 21555107.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21555113) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2613 + ... + 7066.

It is an arithmetic number, because the mean of its divisors is an integer number (2874960).

Almost surely, 2^21555133 is an apocalyptic number.

It is an amenable number.

21555133 is a deficient number, since it is larger than the sum of its proper divisors (1444547).

21555133 is a wasteful number, since it uses less digits than its factorization.

21555133 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9827.

The product of its digits is 2250, while the sum is 25.

The square root of 21555133 is about 4642.7505855904. The cubic root of 21555133 is about 278.3023684183.

It can be divided in two parts, 21555 and 133, that multiplied together give a triangular number (2866815 = T₂₃₉₄).

The spelling of 21555133 in words is "twenty-one million, five hundred fifty-five thousand, one hundred thirty-three".