21013311 has 16 divisors (see below), whose sum is σ = 30774528. Its totient is φ = 12648000.

The previous prime is 21013303. The next prime is 21013357. The reversal of 21013311 is 11331012.

It is not a de Polignac number, because 21013311 - 2³ = 21013303 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21013301) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2875 + ... + 7091.

It is an arithmetic number, because the mean of its divisors is an integer number (1923408).

Almost surely, 2^21013311 is an apocalyptic number.

21013311 is a deficient number, since it is larger than the sum of its proper divisors (9761217).

21013311 is a wasteful number, since it uses less digits than its factorization.

21013311 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4382.

The product of its (nonzero) digits is 18, while the sum is 12.

The square root of 21013311 is about 4584.0278140517. The cubic root of 21013311 is about 275.9506974527.

Adding to 21013311 its reverse (11331012), we get a palindrome (32344323).

The spelling of 21013311 in words is "twenty-one million, thirteen thousand, three hundred eleven".