21553153 has 4 divisors (see below), whose sum is σ = 22248448. Its totient is φ = 20857860.

The previous prime is 21553141. The next prime is 21553157. The reversal of 21553153 is 35135512.

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 a de Polignac number, because none of the positive numbers 2^k-21553153 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21553157) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 347601 + ... + 347662.

It is an arithmetic number, because the mean of its divisors is an integer number (5562112).

It is a Proth number, since it is equal to 2631 ⋅ 2¹³ + 1 and 2631 < 2¹³.

Almost surely, 2^21553153 is an apocalyptic number.

It is an amenable number.

21553153 is a deficient number, since it is larger than the sum of its proper divisors (695295).

21553153 is an equidigital number, since it uses as much as digits as its factorization.

21553153 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 695294.

The product of its digits is 2250, while the sum is 25.

The square root of 21553153 is about 4642.5373450302. The cubic root of 21553153 is about 278.2938467735.

Adding to 21553153 its reverse (35135512), we get a palindrome (56688665).

The spelling of 21553153 in words is "twenty-one million, five hundred fifty-three thousand, one hundred fifty-three".