21020430331 has 4 divisors (see below), whose sum is σ = 21509277592. Its totient is φ = 20531583072.

The previous prime is 21020430313. The next prime is 21020430367. The reversal of 21020430331 is 13303402012.

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

It is a cyclic number.

It is not a de Polignac number, because 21020430331 - 2⁹ = 21020429819 is a prime.

It is a super-2 number, since 2×21020430331² (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 = 21020430299 and 21020430308.

It is not an unprimeable number, because it can be changed into a prime (21020430311) 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, 244423566 + ... + 244423651.

It is an arithmetic number, because the mean of its divisors is an integer number (5377319398).

Almost surely, 2^21020430331 is an apocalyptic number.

21020430331 is a deficient number, since it is larger than the sum of its proper divisors (488847261).

21020430331 is an equidigital number, since it uses as much as digits as its factorization.

21020430331 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 488847260.

The product of its (nonzero) digits is 432, while the sum is 19.

Adding to 21020430331 its reverse (13303402012), we get a palindrome (34323832343).

The spelling of 21020430331 in words is "twenty-one billion, twenty million, four hundred thirty thousand, three hundred thirty-one".