21040006 has 8 divisors (see below), whose sum is σ = 33987744. Its totient is φ = 9710760.

The previous prime is 21040001. The next prime is 21040007. The reversal of 21040006 is 60004012.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a Harshad number since it is a multiple of its sum of digits (13).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21040001) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 404590 + ... + 404641.

It is an arithmetic number, because the mean of its divisors is an integer number (4248468).

Almost surely, 2^21040006 is an apocalyptic number.

21040006 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

21040006 is a deficient number, since it is larger than the sum of its proper divisors (12947738).

21040006 is a wasteful number, since it uses less digits than its factorization.

21040006 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 809246.

The product of its (nonzero) digits is 48, while the sum is 13.

The square root of 21040006 is about 4586.9386305029. The cubic root of 21040006 is about 276.0675025679.

Adding to 21040006 its reverse (60004012), we get a palindrome (81044018).

The spelling of 21040006 in words is "twenty-one million, forty thousand, six".