20510403421 has 4 divisors (see below), whose sum is σ = 20510833500. Its totient is φ = 20509973344.

The previous prime is 20510403413. The next prime is 20510403443. The reversal of 20510403421 is 12430401502.

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 8391476025 + 12118927396 = 91605^2 + 110086^2 .

It is a cyclic number.

It is not a de Polignac number, because 20510403421 - 2³ = 20510403413 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20510403392 and 20510403401.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20510403481) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 133096 + ... + 242353.

It is an arithmetic number, because the mean of its divisors is an integer number (5127708375).

Almost surely, 2^20510403421 is an apocalyptic number.

It is an amenable number.

20510403421 is a deficient number, since it is larger than the sum of its proper divisors (430079).

20510403421 is an equidigital number, since it uses as much as digits as its factorization.

20510403421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 430078.

The product of its (nonzero) digits is 960, while the sum is 22.

Adding to 20510403421 its reverse (12430401502), we get a palindrome (32940804923).

The spelling of 20510403421 in words is "twenty billion, five hundred ten million, four hundred three thousand, four hundred twenty-one".