21523313131 has 8 divisors (see below), whose sum is σ = 23045452560. Its totient is φ = 20029625088.

The previous prime is 21523313099. The next prime is 21523313171. The reversal of 21523313131 is 13131332512.

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 21523313131 - 2⁵ = 21523313099 is a prime.

It is a super-2 number, since 2×21523313131² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21523313096 and 21523313105.

It is not an unprimeable number, because it can be changed into a prime (21523313171) 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, 7111281 + ... + 7114306.

It is an arithmetic number, because the mean of its divisors is an integer number (2880681570).

Almost surely, 2^21523313131 is an apocalyptic number.

21523313131 is a deficient number, since it is larger than the sum of its proper divisors (1522139429).

21523313131 is a wasteful number, since it uses less digits than its factorization.

21523313131 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14225693.

The product of its digits is 1620, while the sum is 25.

Adding to 21523313131 its reverse (13131332512), we get a palindrome (34654645643).

The spelling of 21523313131 in words is "twenty-one billion, five hundred twenty-three million, three hundred thirteen thousand, one hundred thirty-one".