21050242 has 4 divisors (see below), whose sum is σ = 31575366. Its totient is φ = 10525120.

The previous prime is 21050231. The next prime is 21050251. The reversal of 21050242 is 24205012.

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., 19793601 + 1256641 = 4449^2 + 1121^2 .

It is a super-3 number, since 3×21050242³ (a number of 23 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5262559 + ... + 5262562.

Almost surely, 2^21050242 is an apocalyptic number.

21050242 is a deficient number, since it is larger than the sum of its proper divisors (10525124).

21050242 is a wasteful number, since it uses less digits than its factorization.

21050242 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10525123.

The product of its (nonzero) digits is 160, while the sum is 16.

The square root of 21050242 is about 4588.0542716930. The cubic root of 21050242 is about 276.1122644186.

Adding to 21050242 its reverse (24205012), we get a palindrome (45255254).

The spelling of 21050242 in words is "twenty-one million, fifty thousand, two hundred forty-two".