21345207 has 12 divisors (see below), whose sum is σ = 30818664. Its totient is φ = 13135200.

The previous prime is 21345187. The next prime is 21345211. The reversal of 21345207 is 70254312.

It is not a de Polignac number, because 21345207 - 2⁸ = 21344951 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21345277) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 20544 + ... + 21557.

It is an arithmetic number, because the mean of its divisors is an integer number (2568222).

Almost surely, 2^21345207 is an apocalyptic number.

21345207 is a deficient number, since it is larger than the sum of its proper divisors (9473457).

21345207 is a wasteful number, since it uses less digits than its factorization.

21345207 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 42130 (or 42117 counting only the distinct ones).

The product of its (nonzero) digits is 1680, while the sum is 24.

The square root of 21345207 is about 4620.0873368368. The cubic root of 21345207 is about 277.3959548261.

Adding to 21345207 its reverse (70254312), we get a palindrome (91599519).

The spelling of 21345207 in words is "twenty-one million, three hundred forty-five thousand, two hundred seven".