20433421 has 4 divisors (see below), whose sum is σ = 20663100. Its totient is φ = 20203744.

The previous prime is 20433409. The next prime is 20433437. The reversal of 20433421 is 12433402.

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 6817321 + 13616100 = 2611^2 + 3690^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20433421 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20433481) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 114706 + ... + 114883.

It is an arithmetic number, because the mean of its divisors is an integer number (5165775).

Almost surely, 2^20433421 is an apocalyptic number.

It is an amenable number.

20433421 is a deficient number, since it is larger than the sum of its proper divisors (229679).

20433421 is an equidigital number, since it uses as much as digits as its factorization.

20433421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 229678.

The product of its (nonzero) digits is 576, while the sum is 19.

The square root of 20433421 is about 4520.3341690632. The cubic root of 20433421 is about 273.3885748286.

Subtracting from 20433421 its sum of digits (19), we obtain a palindrome (20433402).

Adding to 20433421 its reverse (12433402), we get a palindrome (32866823).

The spelling of 20433421 in words is "twenty million, four hundred thirty-three thousand, four hundred twenty-one".