21421006 has 8 divisors (see below), whose sum is σ = 32185440. Its totient is φ = 10692528.

The previous prime is 21420991. The next prime is 21421051. The reversal of 21421006 is 60012412.

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, 7446 + ... + 9913.

It is an arithmetic number, because the mean of its divisors is an integer number (4023180).

Almost surely, 2^21421006 is an apocalyptic number.

21421006 is a deficient number, since it is larger than the sum of its proper divisors (10764434).

21421006 is a wasteful number, since it uses less digits than its factorization.

21421006 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17978.

The product of its (nonzero) digits is 96, while the sum is 16.

The square root of 21421006 is about 4628.2832670441. The cubic root of 21421006 is about 277.7239206637.

Adding to 21421006 its reverse (60012412), we get a palindrome (81433418).

The spelling of 21421006 in words is "twenty-one million, four hundred twenty-one thousand, six".