21203533 has 8 divisors (see below), whose sum is σ = 23321088. Its totient is φ = 19155504.

The previous prime is 21203513. The next prime is 21203543. The reversal of 21203533 is 33530212.

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 21203533 - 2¹³ = 21195341 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21203533.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21203503) 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 7 ways as a sum of consecutive naturals, for example, 16741 + ... + 17962.

It is an arithmetic number, because the mean of its divisors is an integer number (2915136).

Almost surely, 2^21203533 is an apocalyptic number.

It is an amenable number.

21203533 is a deficient number, since it is larger than the sum of its proper divisors (2117555).

21203533 is a wasteful number, since it uses less digits than its factorization.

21203533 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 34763.

The product of its (nonzero) digits is 540, while the sum is 19.

The square root of 21203533 is about 4604.7294165890. The cubic root of 21203533 is about 276.7808742855.

Adding to 21203533 its reverse (33530212), we get a palindrome (54733745).

It can be divided in two parts, 21203 and 533, that added together give a triangular number (21736 = T₂₀₈).

The spelling of 21203533 in words is "twenty-one million, two hundred three thousand, five hundred thirty-three".