21309153 has 8 divisors (see below), whose sum is σ = 28587168. Its totient is φ = 14118624.

The previous prime is 21309133. The next prime is 21309179. The reversal of 21309153 is 35190312.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21309153 - 2⁸ = 21308897 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21309103) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 21300 + ... + 22277.

It is an arithmetic number, because the mean of its divisors is an integer number (3573396).

Almost surely, 2^21309153 is an apocalyptic number.

It is an amenable number.

21309153 is a deficient number, since it is larger than the sum of its proper divisors (7278015).

21309153 is a wasteful number, since it uses less digits than its factorization.

21309153 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 43743.

The product of its (nonzero) digits is 810, while the sum is 24.

The square root of 21309153 is about 4616.1838134979. The cubic root of 21309153 is about 277.2396844583.

Adding to 21309153 its reverse (35190312), we get a palindrome (56499465).

The spelling of 21309153 in words is "twenty-one million, three hundred nine thousand, one hundred fifty-three".