20387832821 has 4 divisors (see below), whose sum is σ = 20861968512. Its totient is φ = 19913697132.

The previous prime is 20387832781. The next prime is 20387832847. The reversal of 20387832821 is 12823878302.

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 20387832821 - 2³⁴ = 3207963637 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 (20387832721) 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, 237067781 + ... + 237067866.

It is an arithmetic number, because the mean of its divisors is an integer number (5215492128).

Almost surely, 2^20387832821 is an apocalyptic number.

It is an amenable number.

20387832821 is a deficient number, since it is larger than the sum of its proper divisors (474135691).

20387832821 is an equidigital number, since it uses as much as digits as its factorization.

20387832821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 474135690.

The product of its (nonzero) digits is 258048, while the sum is 44.

The spelling of 20387832821 in words is "twenty billion, three hundred eighty-seven million, eight hundred thirty-two thousand, eight hundred twenty-one".