21420320411 has 4 divisors (see below), whose sum is σ = 24480366192. Its totient is φ = 18360274632.

The previous prime is 21420320407. The next prime is 21420320543. The reversal of 21420320411 is 11402302412.

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

It is not a de Polignac number, because 21420320411 - 2² = 21420320407 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21420328411) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1530022880 + ... + 1530022893.

It is an arithmetic number, because the mean of its divisors is an integer number (6120091548).

Almost surely, 2^21420320411 is an apocalyptic number.

21420320411 is a deficient number, since it is larger than the sum of its proper divisors (3060045781).

21420320411 is an equidigital number, since it uses as much as digits as its factorization.

21420320411 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3060045780.

The product of its (nonzero) digits is 384, while the sum is 20.

Adding to 21420320411 its reverse (11402302412), we get a palindrome (32822622823).

The spelling of 21420320411 in words is "twenty-one billion, four hundred twenty million, three hundred twenty thousand, four hundred eleven".