21234553 has 4 divisors (see below), whose sum is σ = 21686400. Its totient is φ = 20782708.

The previous prime is 21234541. The next prime is 21234593. The reversal of 21234553 is 35543212.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21234553 - 2²¹ = 19137401 is a prime.

It is a super-2 number, since 2×21234553² = 901812482219618, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21234523) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 225853 + ... + 225946.

It is an arithmetic number, because the mean of its divisors is an integer number (5421600).

Almost surely, 2^21234553 is an apocalyptic number.

It is an amenable number.

21234553 is a deficient number, since it is larger than the sum of its proper divisors (451847).

21234553 is an equidigital number, since it uses as much as digits as its factorization.

21234553 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 451846.

The product of its digits is 3600, while the sum is 25.

The square root of 21234553 is about 4608.0964616640. The cubic root of 21234553 is about 276.9157819798.

Adding to 21234553 its reverse (35543212), we get a palindrome (56777765).

The spelling of 21234553 in words is "twenty-one million, two hundred thirty-four thousand, five hundred fifty-three".