21000411 has 16 divisors (see below), whose sum is σ = 31489920. Its totient is φ = 13830120.

The previous prime is 21000407. The next prime is 21000433. The reversal of 21000411 is 11400012.

It is a happy number.

It is not a de Polignac number, because 21000411 - 2² = 21000407 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a junction number, because it is equal to n+sod(n) for n = 21000393 and 21000402.

It is not an unprimeable number, because it can be changed into a prime (21000461) 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 15 ways as a sum of consecutive naturals, for example, 2445 + ... + 6926.

It is an arithmetic number, because the mean of its divisors is an integer number (1968120).

Almost surely, 2^21000411 is an apocalyptic number.

21000411 is a deficient number, since it is larger than the sum of its proper divisors (10489509).

21000411 is an equidigital number, since it uses as much as digits as its factorization.

21000411 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9463 (or 9457 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 9.

The square root of 21000411 is about 4582.6205385129. The cubic root of 21000411 is about 275.8942174960.

Adding to 21000411 its reverse (11400012), we get a palindrome (32400423).

The spelling of 21000411 in words is "twenty-one million, four hundred eleven", and thus it is an aban number.