20421351533 has 4 divisors (see below), whose sum is σ = 22277838048. Its totient is φ = 18564865020.

The previous prime is 20421351529. The next prime is 20421351539. The reversal of 20421351533 is 33515312402.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 20421351533 - 2² = 20421351529 is a prime.

It is a super-2 number, since 2×20421351533² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20421351496 and 20421351505.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20421351539) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 928243241 + ... + 928243262.

It is an arithmetic number, because the mean of its divisors is an integer number (5569459512).

Almost surely, 2^20421351533 is an apocalyptic number.

It is an amenable number.

20421351533 is a deficient number, since it is larger than the sum of its proper divisors (1856486515).

20421351533 is a wasteful number, since it uses less digits than its factorization.

20421351533 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1856486514.

The product of its (nonzero) digits is 10800, while the sum is 29.

Adding to 20421351533 its reverse (33515312402), we get a palindrome (53936663935).

The spelling of 20421351533 in words is "twenty billion, four hundred twenty-one million, three hundred fifty-one thousand, five hundred thirty-three".