21024207 has 6 divisors (see below), whose sum is σ = 30368312. Its totient is φ = 14016132.

The previous prime is 21024197. The next prime is 21024209. The reversal of 21024207 is 70242012.

It is not a de Polignac number, because 21024207 - 2¹⁰ = 21023183 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21024207.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21024209) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1168003 + ... + 1168020.

Almost surely, 2^21024207 is an apocalyptic number.

21024207 is a deficient number, since it is larger than the sum of its proper divisors (9344105).

21024207 is a wasteful number, since it uses less digits than its factorization.

21024207 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2336029 (or 2336026 counting only the distinct ones).

The product of its (nonzero) digits is 224, while the sum is 18.

The square root of 21024207 is about 4585.2161344914. The cubic root of 21024207 is about 275.9983853088.

Adding to 21024207 its reverse (70242012), we get a palindrome (91266219).

The spelling of 21024207 in words is "twenty-one million, twenty-four thousand, two hundred seven".