21761242 has 8 divisors (see below), whose sum is σ = 33438132. Its totient is φ = 10615200.

The previous prime is 21761239. The next prime is 21761249. The reversal of 21761242 is 24216712.

It can be written as a sum of positive squares in 2 ways, for example, as 20875761 + 885481 = 4569^2 + 941^2 .

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

It is not an unprimeable number, because it can be changed into a prime (21761249) 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 3 ways as a sum of consecutive naturals, for example, 132609 + ... + 132772.

Almost surely, 2^21761242 is an apocalyptic number.

21761242 is a deficient number, since it is larger than the sum of its proper divisors (11676890).

21761242 is a wasteful number, since it uses less digits than its factorization.

21761242 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 265424.

The product of its digits is 1344, while the sum is 25.

The square root of 21761242 is about 4664.8946397534. The cubic root of 21761242 is about 279.1865934045.

Adding to 21761242 its reverse (24216712), we get a palindrome (45977954).

The spelling of 21761242 in words is "twenty-one million, seven hundred sixty-one thousand, two hundred forty-two".