21315153 has 4 divisors (see below), whose sum is σ = 28420208. Its totient is φ = 14210100.

The previous prime is 21315139. The next prime is 21315163. The reversal of 21315153 is 35151312.

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 not a de Polignac number, because 21315153 - 2⁴ = 21315137 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21315163) 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, 3552523 + ... + 3552528.

It is an arithmetic number, because the mean of its divisors is an integer number (7105052).

Almost surely, 2^21315153 is an apocalyptic number.

It is an amenable number.

21315153 is a deficient number, since it is larger than the sum of its proper divisors (7105055).

21315153 is an equidigital number, since it uses as much as digits as its factorization.

21315153 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7105054.

The product of its digits is 450, while the sum is 21.

The square root of 21315153 is about 4616.8336552230. The cubic root of 21315153 is about 277.2657027302.

Adding to 21315153 its reverse (35151312), we get a palindrome (56466465).

The spelling of 21315153 in words is "twenty-one million, three hundred fifteen thousand, one hundred fifty-three".