21007211 has 8 divisors (see below), whose sum is σ = 22456224. Its totient is φ = 19602880.

The previous prime is 21007201. The next prime is 21007213. The reversal of 21007211 is 11270012.

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

It is a cyclic number.

It is not a de Polignac number, because 21007211 - 2²² = 16812907 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21007213) 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 7 ways as a sum of consecutive naturals, for example, 10196 + ... + 12081.

It is an arithmetic number, because the mean of its divisors is an integer number (2807028).

Almost surely, 2^21007211 is an apocalyptic number.

21007211 is a deficient number, since it is larger than the sum of its proper divisors (1449013).

21007211 is a wasteful number, since it uses less digits than its factorization.

21007211 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22341.

The product of its (nonzero) digits is 28, while the sum is 14.

The square root of 21007211 is about 4583.3624120290. The cubic root of 21007211 is about 275.9239927580.

Adding to 21007211 its reverse (11270012), we get a palindrome (32277223).

The spelling of 21007211 in words is "twenty-one million, seven thousand, two hundred eleven".