21225533 has 16 divisors (see below), whose sum is σ = 24858624. Its totient is φ = 17748720.

The previous prime is 21225511. The next prime is 21225541. The reversal of 21225533 is 33552212.

It is a cyclic number.

It is not a de Polignac number, because 21225533 - 2⁸ = 21225277 is a prime.

It is a super-2 number, since 2×21225533² = 901046502268178, which contains 22 as substring.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21225499 and 21225508.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21225563) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 78188 + ... + 78458.

It is an arithmetic number, because the mean of its divisors is an integer number (1553664).

Almost surely, 2^21225533 is an apocalyptic number.

It is an amenable number.

21225533 is a deficient number, since it is larger than the sum of its proper divisors (3633091).

21225533 is a wasteful number, since it uses less digits than its factorization.

21225533 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 512.

The product of its digits is 1800, while the sum is 23.

The square root of 21225533 is about 4607.1176455567. The cubic root of 21225533 is about 276.8765670564.

Adding to 21225533 its reverse (33552212), we get a palindrome (54777745).

The spelling of 21225533 in words is "twenty-one million, two hundred twenty-five thousand, five hundred thirty-three".