21180242 has 8 divisors (see below), whose sum is σ = 31973196. Its totient is φ = 10522512.

The previous prime is 21180239. The next prime is 21180281. The reversal of 21180242 is 24208112.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 18156121 + 3024121 = 4261^2 + 1739^2 .

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

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 33413 + ... + 34040.

Almost surely, 2^21180242 is an apocalyptic number.

21180242 is a deficient number, since it is larger than the sum of its proper divisors (10792954).

21180242 is a wasteful number, since it uses less digits than its factorization.

21180242 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 67612.

The product of its (nonzero) digits is 256, while the sum is 20.

The square root of 21180242 is about 4602.1996914519. The cubic root of 21180242 is about 276.6794939296.

Adding to 21180242 its reverse (24208112), we get a palindrome (45388354).

The spelling of 21180242 in words is "twenty-one million, one hundred eighty thousand, two hundred forty-two".