21013130321 has 16 divisors (see below), whose sum is σ = 21542661504. Its totient is φ = 20488925184.

The previous prime is 21013130287. The next prime is 21013130377. The reversal of 21013130321 is 12303131012.

It is a cyclic number.

It is not a de Polignac number, because 21013130321 - 2²² = 21008936017 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21013130321.

It is not an unprimeable number, because it can be changed into a prime (21013130521) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6849830 + ... + 6852896.

It is an arithmetic number, because the mean of its divisors is an integer number (1346416344).

Almost surely, 2^21013130321 is an apocalyptic number.

It is an amenable number.

21013130321 is a deficient number, since it is larger than the sum of its proper divisors (529531183).

21013130321 is a wasteful number, since it uses less digits than its factorization.

21013130321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3880.

The product of its (nonzero) digits is 108, while the sum is 17.

Adding to 21013130321 its reverse (12303131012), we get a palindrome (33316261333).

The spelling of 21013130321 in words is "twenty-one billion, thirteen million, one hundred thirty thousand, three hundred twenty-one".