21420310331 has 4 divisors (see below), whose sum is σ = 24480354672. Its totient is φ = 18360265992.

The previous prime is 21420310319. The next prime is 21420310399. The reversal of 21420310331 is 13301302412.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21420310331 is a prime.

It is a super-2 number, since 2×21420310331² (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 (21420310631) 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, 1530022160 + ... + 1530022173.

It is an arithmetic number, because the mean of its divisors is an integer number (6120088668).

Almost surely, 2^21420310331 is an apocalyptic number.

21420310331 is a deficient number, since it is larger than the sum of its proper divisors (3060044341).

21420310331 is an equidigital number, since it uses as much as digits as its factorization.

21420310331 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3060044340.

The product of its (nonzero) digits is 432, while the sum is 20.

Adding to 21420310331 its reverse (13301302412), we get a palindrome (34721612743).

The spelling of 21420310331 in words is "twenty-one billion, four hundred twenty million, three hundred ten thousand, three hundred thirty-one".