21207634 has 8 divisors (see below), whose sum is σ = 36355968. Its totient is φ = 9088980.

The previous prime is 21207631. The next prime is 21207649. The reversal of 21207634 is 43670212.

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

It is a junction number, because it is equal to n+sod(n) for n = 21207599 and 21207608.

It is not an unprimeable number, because it can be changed into a prime (21207631) 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 3 ways as a sum of consecutive naturals, for example, 757402 + ... + 757429.

It is an arithmetic number, because the mean of its divisors is an integer number (4544496).

Almost surely, 2^21207634 is an apocalyptic number.

21207634 is a deficient number, since it is larger than the sum of its proper divisors (15148334).

21207634 is a wasteful number, since it uses less digits than its factorization.

21207634 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1514840.

The product of its (nonzero) digits is 2016, while the sum is 25.

The square root of 21207634 is about 4605.1746980978. The cubic root of 21207634 is about 276.7987173056.

Adding to 21207634 its reverse (43670212), we get a palindrome (64877846).

The spelling of 21207634 in words is "twenty-one million, two hundred seven thousand, six hundred thirty-four".