21006446 has 8 divisors (see below), whose sum is σ = 32242584. Its totient is φ = 10258920.

The previous prime is 21006439. The next prime is 21006451. The reversal of 21006446 is 64460012.

It is a happy number.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 122045 + ... + 122216.

It is an arithmetic number, because the mean of its divisors is an integer number (4030323).

Almost surely, 2^21006446 is an apocalyptic number.

21006446 is a deficient number, since it is larger than the sum of its proper divisors (11236138).

21006446 is a wasteful number, since it uses less digits than its factorization.

21006446 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 244306.

The product of its (nonzero) digits is 1152, while the sum is 23.

The square root of 21006446 is about 4583.2789572532. The cubic root of 21006446 is about 275.9206433618.

Adding to 21006446 its reverse (64460012), we get a palindrome (85466458).

The spelling of 21006446 in words is "twenty-one million, six thousand, four hundred forty-six".