21545153 has 6 divisors (see below), whose sum is σ = 25062786. Its totient is φ = 18467232.

The previous prime is 21545149. The next prime is 21545179. The reversal of 21545153 is 35154512.

It can be written as a sum of positive squares in only one way, i.e., 20638849 + 906304 = 4543^2 + 952^2 .

It is not a de Polignac number, because 21545153 - 2² = 21545149 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21545353) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 219800 + ... + 219897.

It is an arithmetic number, because the mean of its divisors is an integer number (4177131).

Almost surely, 2^21545153 is an apocalyptic number.

It is an amenable number.

21545153 is a deficient number, since it is larger than the sum of its proper divisors (3517633).

21545153 is an equidigital number, since it uses as much as digits as its factorization.

21545153 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 439711 (or 439704 counting only the distinct ones).

The product of its digits is 3000, while the sum is 26.

The square root of 21545153 is about 4641.6756672564. The cubic root of 21545153 is about 278.2594105700.

Adding to 21545153 its reverse (35154512), we get a palindrome (56699665).

The spelling of 21545153 in words is "twenty-one million, five hundred forty-five thousand, one hundred fifty-three".