21420311 has 8 divisors (see below), whose sum is σ = 23447424. Its totient is φ = 19406520.

The previous prime is 21420293. The next prime is 21420331. The reversal of 21420311 is 11302412.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21420311 - 2¹⁰ = 21419287 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21420331) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 206 + ... + 6548.

It is an arithmetic number, because the mean of its divisors is an integer number (2930928).

Almost surely, 2^21420311 is an apocalyptic number.

21420311 is a deficient number, since it is larger than the sum of its proper divisors (2027113).

21420311 is a wasteful number, since it uses less digits than its factorization.

21420311 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6661.

The product of its (nonzero) digits is 48, while the sum is 14.

The square root of 21420311 is about 4628.2081846002. The cubic root of 21420311 is about 277.7209170667.

Adding to 21420311 its reverse (11302412), we get a palindrome (32722723).

The spelling of 21420311 in words is "twenty-one million, four hundred twenty thousand, three hundred eleven".