20242421 has 4 divisors (see below), whose sum is σ = 20282700. Its totient is φ = 20202144.

The previous prime is 20242373. The next prime is 20242433. The reversal of 20242421 is 12424202.

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 2 ways, for example, as 9424900 + 10817521 = 3070^2 + 3289^2 .

It is a cyclic number.

It is not a de Polignac number, because 20242421 - 2²² = 16048117 is a prime.

It is a super-3 number, since 3×20242421³ (a number of 23 digits) contains 333 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20242421.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20242451) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 19376 + ... + 20393.

It is an arithmetic number, because the mean of its divisors is an integer number (5070675).

Almost surely, 2^20242421 is an apocalyptic number.

It is an amenable number.

20242421 is a deficient number, since it is larger than the sum of its proper divisors (40279).

20242421 is an equidigital number, since it uses as much as digits as its factorization.

20242421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40278.

The product of its (nonzero) digits is 256, while the sum is 17.

The square root of 20242421 is about 4499.1578100796. The cubic root of 20242421 is about 272.5340798496.

Adding to 20242421 its reverse (12424202), we get a palindrome (32666623).

The spelling of 20242421 in words is "twenty million, two hundred forty-two thousand, four hundred twenty-one".