21001320331 has 8 divisors (see below), whose sum is σ = 22523760720. Its totient is φ = 19520590752.

The previous prime is 21001320323. The next prime is 21001320343. The reversal of 21001320331 is 13302310012.

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 21001320331 - 2³ = 21001320323 is a prime.

It is a super-2 number, since 2×21001320331² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21001320371) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10426660 + ... + 10428673.

It is an arithmetic number, because the mean of its divisors is an integer number (2815470090).

Almost surely, 2^21001320331 is an apocalyptic number.

21001320331 is a deficient number, since it is larger than the sum of its proper divisors (1522440389).

21001320331 is a wasteful number, since it uses less digits than its factorization.

21001320331 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20855405.

The product of its (nonzero) digits is 108, while the sum is 16.

Adding to 21001320331 its reverse (13302310012), we get a palindrome (34303630343).

The spelling of 21001320331 in words is "twenty-one billion, one million, three hundred twenty thousand, three hundred thirty-one".