21023311 has 8 divisors (see below), whose sum is σ = 22134240. Its totient is φ = 19928832.

The previous prime is 21023309. The next prime is 21023323. The reversal of 21023311 is 11332012.

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 21023311 - 2¹ = 21023309 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21023291 and 21023300.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21023341) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1446 + ... + 6643.

It is an arithmetic number, because the mean of its divisors is an integer number (2766780).

Almost surely, 2^21023311 is an apocalyptic number.

21023311 is a deficient number, since it is larger than the sum of its proper divisors (1110929).

21023311 is a wasteful number, since it uses less digits than its factorization.

21023311 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8225.

The product of its (nonzero) digits is 36, while the sum is 13.

The square root of 21023311 is about 4585.1184281325. The cubic root of 21023311 is about 275.9944644622.

Adding to 21023311 its reverse (11332012), we get a palindrome (32355323).

The spelling of 21023311 in words is "twenty-one million, twenty-three thousand, three hundred eleven".