21030213531 has 4 divisors (see below), whose sum is σ = 28040284712. Its totient is φ = 14020142352.

The previous prime is 21030213521. The next prime is 21030213559. The reversal of 21030213531 is 13531203012.

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

It is not a de Polignac number, because 21030213531 - 2⁵ = 21030213499 is a prime.

It is a super-2 number, since 2×21030213531² (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 = 21030213498 and 21030213507.

It is not an unprimeable number, because it can be changed into a prime (21030213521) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3505035586 + ... + 3505035591.

It is an arithmetic number, because the mean of its divisors is an integer number (7010071178).

Almost surely, 2^21030213531 is an apocalyptic number.

21030213531 is a deficient number, since it is larger than the sum of its proper divisors (7010071181).

21030213531 is an equidigital number, since it uses as much as digits as its factorization.

21030213531 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7010071180.

The product of its (nonzero) digits is 540, while the sum is 21.

Adding to 21030213531 its reverse (13531203012), we get a palindrome (34561416543).

The spelling of 21030213531 in words is "twenty-one billion, thirty million, two hundred thirteen thousand, five hundred thirty-one".