21011031321 has 8 divisors (see below), whose sum is σ = 32016809664. Its totient is φ = 12006303600.

The previous prime is 21011031299. The next prime is 21011031329. The reversal of 21011031321 is 12313011012.

It is a happy number.

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

It is a de Polignac number, because none of the positive numbers 2^k-21011031321 is a prime.

It is a super-3 number, since 3×21011031321³ (a number of 32 digits) contains 333 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21011031321.

It is not an unprimeable number, because it can be changed into a prime (21011031329) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 500262630 + ... + 500262671.

It is an arithmetic number, because the mean of its divisors is an integer number (4002101208).

Almost surely, 2^21011031321 is an apocalyptic number.

21011031321 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

21011031321 is a deficient number, since it is larger than the sum of its proper divisors (11005778343).

21011031321 is a wasteful number, since it uses less digits than its factorization.

21011031321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1000525311.

The product of its (nonzero) digits is 36, while the sum is 15.

Adding to 21011031321 its reverse (12313011012), we get a palindrome (33324042333).

The spelling of 21011031321 in words is "twenty-one billion, eleven million, thirty-one thousand, three hundred twenty-one".