21011020321 has 4 divisors (see below), whose sum is σ = 21069547200. Its totient is φ = 20952493444.

The previous prime is 21011020313. The next prime is 21011020333. The reversal of 21011020321 is 12302011012.

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 21011020321 - 2³ = 21011020313 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21011020301) 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, 29262901 + ... + 29263618.

It is an arithmetic number, because the mean of its divisors is an integer number (5267386800).

Almost surely, 2^21011020321 is an apocalyptic number.

It is an amenable number.

21011020321 is a deficient number, since it is larger than the sum of its proper divisors (58526879).

21011020321 is an equidigital number, since it uses as much as digits as its factorization.

21011020321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 58526878.

The product of its (nonzero) digits is 24, while the sum is 13.

Adding to 21011020321 its reverse (12302011012), we get a palindrome (33313031333).

The spelling of 21011020321 in words is "twenty-one billion, eleven million, twenty thousand, three hundred twenty-one".