21217433 has 8 divisors (see below), whose sum is σ = 22394400. Its totient is φ = 20046528.

The previous prime is 21217421. The next prime is 21217453. The reversal of 21217433 is 33471212.

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 21217433 - 2¹⁰ = 21216409 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21217399 and 21217408.

It is not an unprimeable number, because it can be changed into a prime (21217453) 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, 6938 + ... + 9516.

It is an arithmetic number, because the mean of its divisors is an integer number (2799300).

Almost surely, 2^21217433 is an apocalyptic number.

It is an amenable number.

21217433 is a deficient number, since it is larger than the sum of its proper divisors (1176967).

21217433 is a wasteful number, since it uses less digits than its factorization.

21217433 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3031.

The product of its digits is 1008, while the sum is 23.

The square root of 21217433 is about 4606.2384870955. The cubic root of 21217433 is about 276.8413424123.

Adding to 21217433 its reverse (33471212), we get a palindrome (54688645).

It can be divided in two parts, 21217 and 433, that multiplied together give a square (9186961 = 3031²).

The spelling of 21217433 in words is "twenty-one million, two hundred seventeen thousand, four hundred thirty-three".