21153241 has 4 divisors (see below), whose sum is σ = 21186000. Its totient is φ = 21120484.

The previous prime is 21153227. The next prime is 21153257. The reversal of 21153241 is 14235112.

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 21153241 - 2⁷ = 21153113 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21153281) 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, 15391 + ... + 16708.

It is an arithmetic number, because the mean of its divisors is an integer number (5296500).

Almost surely, 2^21153241 is an apocalyptic number.

It is an amenable number.

21153241 is a deficient number, since it is larger than the sum of its proper divisors (32759).

21153241 is an equidigital number, since it uses as much as digits as its factorization.

21153241 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32758.

The product of its digits is 240, while the sum is 19.

The square root of 21153241 is about 4599.2652674096. The cubic root of 21153241 is about 276.5618717319.

Adding to 21153241 its reverse (14235112), we get a palindrome (35388353).

It can be divided in two parts, 2115 and 3241, that added together give a triangular number (5356 = T₁₀₃).

The spelling of 21153241 in words is "twenty-one million, one hundred fifty-three thousand, two hundred forty-one".