21010207 has 8 divisors (see below), whose sum is σ = 21486384. Its totient is φ = 20537088.

The previous prime is 21010193. The next prime is 21010217. The reversal of 21010207 is 70201012.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21010207 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21010217) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 18148 + ... + 19270.

It is an arithmetic number, because the mean of its divisors is an integer number (2685798).

Almost surely, 2^21010207 is an apocalyptic number.

21010207 is a deficient number, since it is larger than the sum of its proper divisors (476177).

21010207 is a wasteful number, since it uses less digits than its factorization.

21010207 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1529.

The product of its (nonzero) digits is 28, while the sum is 13.

The square root of 21010207 is about 4583.6892346668. The cubic root of 21010207 is about 275.9371093490.

Adding to 21010207 its reverse (70201012), we get a palindrome (91211219).

The spelling of 21010207 in words is "twenty-one million, ten thousand, two hundred seven".