21321313021 has 8 divisors (see below), whose sum is σ = 22021708544. Its totient is φ = 20621705760.

The previous prime is 21321312989. The next prime is 21321313061. The reversal of 21321313021 is 12031312312.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21321313021 - 2⁵ = 21321312989 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 21321313021.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21321313061) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 141831 + ... + 250516.

It is an arithmetic number, because the mean of its divisors is an integer number (2752713568).

Almost surely, 2^21321313021 is an apocalyptic number.

It is an amenable number.

21321313021 is a deficient number, since it is larger than the sum of its proper divisors (700395523).

21321313021 is a wasteful number, since it uses less digits than its factorization.

21321313021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 394131.

The product of its (nonzero) digits is 216, while the sum is 19.

Adding to 21321313021 its reverse (12031312312), we get a palindrome (33352625333).

The spelling of 21321313021 in words is "twenty-one billion, three hundred twenty-one million, three hundred thirteen thousand, twenty-one".