21040311 has 8 divisors (see below), whose sum is σ = 28583280. Its totient is φ = 13762112.

The previous prime is 21040297. The next prime is 21040387. The reversal of 21040311 is 11304012.

It is a happy number.

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 21040311 - 2⁶ = 21040247 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21040111) 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, 66006 + ... + 66323.

It is an arithmetic number, because the mean of its divisors is an integer number (3572910).

Almost surely, 2^21040311 is an apocalyptic number.

21040311 is a deficient number, since it is larger than the sum of its proper divisors (7542969).

21040311 is a wasteful number, since it uses less digits than its factorization.

21040311 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 132385.

The product of its (nonzero) digits is 24, while the sum is 12.

The square root of 21040311 is about 4586.9718769576. The cubic root of 21040311 is about 276.0688365374.

Adding to 21040311 its reverse (11304012), we get a palindrome (32344323).

The spelling of 21040311 in words is "twenty-one million, forty thousand, three hundred eleven".