21124311 has 16 divisors (see below), whose sum is σ = 30527616. Its totient is φ = 12915936.

The previous prime is 21124289. The next prime is 21124321. The reversal of 21124311 is 11342112.

It is not a de Polignac number, because 21124311 - 2¹⁰ = 21123287 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21124321) 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, 4696 + ... + 8018.

It is an arithmetic number, because the mean of its divisors is an integer number (1907976).

Almost surely, 2^21124311 is an apocalyptic number.

21124311 is a deficient number, since it is larger than the sum of its proper divisors (9403305).

21124311 is a wasteful number, since it uses less digits than its factorization.

21124311 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3502.

The product of its digits is 48, while the sum is 15.

The square root of 21124311 is about 4596.1191237826. The cubic root of 21124311 is about 276.4357352660.

Adding to 21124311 its reverse (11342112), we get a palindrome (32466423).

The spelling of 21124311 in words is "twenty-one million, one hundred twenty-four thousand, three hundred eleven".