21135207 has 8 divisors (see below), whose sum is σ = 28237680. Its totient is φ = 14061440.

The previous prime is 21135173. The next prime is 21135223. The reversal of 21135207 is 70253112.

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 21135207 - 2⁶ = 21135143 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21135227) 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, 5394 + ... + 8447.

It is an arithmetic number, because the mean of its divisors is an integer number (3529710).

Almost surely, 2^21135207 is an apocalyptic number.

21135207 is a deficient number, since it is larger than the sum of its proper divisors (7102473).

21135207 is a wasteful number, since it uses less digits than its factorization.

21135207 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14353.

The product of its (nonzero) digits is 420, while the sum is 21.

The square root of 21135207 is about 4597.3043188373. The cubic root of 21135207 is about 276.4832559645.

Adding to 21135207 its reverse (70253112), we get a palindrome (91388319).

The spelling of 21135207 in words is "twenty-one million, one hundred thirty-five thousand, two hundred seven".