20646135421 has 4 divisors (see below), whose sum is σ = 20646620512. Its totient is φ = 20645650332.

The previous prime is 20646135409. The next prime is 20646135487. The reversal of 20646135421 is 12453164602.

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 20646135421 - 2⁹ = 20646134909 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 (20646135221) 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, 171831 + ... + 266116.

It is an arithmetic number, because the mean of its divisors is an integer number (5161655128).

Almost surely, 2^20646135421 is an apocalyptic number.

It is an amenable number.

20646135421 is a deficient number, since it is larger than the sum of its proper divisors (485091).

20646135421 is an equidigital number, since it uses as much as digits as its factorization.

20646135421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 485090.

The product of its (nonzero) digits is 34560, while the sum is 34.

The spelling of 20646135421 in words is "twenty billion, six hundred forty-six million, one hundred thirty-five thousand, four hundred twenty-one".