21135154 has 4 divisors (see below), whose sum is σ = 31702734. Its totient is φ = 10567576.

The previous prime is 21135151. The next prime is 21135161. The reversal of 21135154 is 45153112.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 16184529 + 4950625 = 4023^2 + 2225^2 .

It is not an unprimeable number, because it can be changed into a prime (21135151) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5283787 + ... + 5283790.

Almost surely, 2^21135154 is an apocalyptic number.

21135154 is a deficient number, since it is larger than the sum of its proper divisors (10567580).

21135154 is a wasteful number, since it uses less digits than its factorization.

21135154 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10567579.

The product of its digits is 600, while the sum is 22.

The square root of 21135154 is about 4597.2985545862. The cubic root of 21135154 is about 276.4830248553.

Adding to 21135154 its reverse (45153112), we get a palindrome (66288266).

The spelling of 21135154 in words is "twenty-one million, one hundred thirty-five thousand, one hundred fifty-four".