21242641 has 8 divisors (see below), whose sum is σ = 24312960. Its totient is φ = 18181248.

The previous prime is 21242629. The next prime is 21242651. The reversal of 21242641 is 14624212.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 21242641 - 2¹⁵ = 21209873 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21242651) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4065 + ... + 7681.

It is an arithmetic number, because the mean of its divisors is an integer number (3039120).

Almost surely, 2^21242641 is an apocalyptic number.

It is an amenable number.

21242641 is a deficient number, since it is larger than the sum of its proper divisors (3070319).

21242641 is an equidigital number, since it uses as much as digits as its factorization.

21242641 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4463.

The product of its digits is 768, while the sum is 22.

The square root of 21242641 is about 4608.9739639100. The cubic root of 21242641 is about 276.9509355421.

Adding to 21242641 its reverse (14624212), we get a palindrome (35866853).

The spelling of 21242641 in words is "twenty-one million, two hundred forty-two thousand, six hundred forty-one".