21111303531 has 4 divisors (see below), whose sum is σ = 28148404712. Its totient is φ = 14074202352.

The previous prime is 21111303517. The next prime is 21111303533. The reversal of 21111303531 is 13530311112.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 21111303531 - 2⁹ = 21111303019 is a prime.

It is a super-2 number, since 2×21111303531² (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 = 21111303498 and 21111303507.

It is not an unprimeable number, because it can be changed into a prime (21111303533) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3518550586 + ... + 3518550591.

It is an arithmetic number, because the mean of its divisors is an integer number (7037101178).

Almost surely, 2^21111303531 is an apocalyptic number.

21111303531 is a deficient number, since it is larger than the sum of its proper divisors (7037101181).

21111303531 is an equidigital number, since it uses as much as digits as its factorization.

21111303531 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7037101180.

The product of its (nonzero) digits is 270, while the sum is 21.

Adding to 21111303531 its reverse (13530311112), we get a palindrome (34641614643).

The spelling of 21111303531 in words is "twenty-one billion, one hundred eleven million, three hundred three thousand, five hundred thirty-one".