21315333017 has 18 divisors (see below), whose sum is σ = 23987039706. Its totient is φ = 18926735520.

The previous prime is 21315332963. The next prime is 21315333031. The reversal of 21315333017 is 71033351312.

It can be written as a sum of positive squares in only one way, i.e., 21086234521 + 229098496 = 145211^2 + 15136^2 .

It is not a de Polignac number, because 21315333017 - 2⁶ = 21315332953 is a prime.

It is a super-2 number, since 2×21315333017² (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 (21315333047) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 176093 + ... + 271365.

It is an arithmetic number, because the mean of its divisors is an integer number (1332613317).

Almost surely, 2^21315333017 is an apocalyptic number.

It is an amenable number.

21315333017 is a deficient number, since it is larger than the sum of its proper divisors (2671706689).

21315333017 is an equidigital number, since it uses as much as digits as its factorization.

21315333017 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 95381 (or 95327 counting only the distinct ones).

The product of its (nonzero) digits is 5670, while the sum is 29.

Adding to 21315333017 its reverse (71033351312), we get a palindrome (92348684329).

The spelling of 21315333017 in words is "twenty-one billion, three hundred fifteen million, three hundred thirty-three thousand, seventeen".