21363634 has 4 divisors (see below), whose sum is σ = 32045454. Its totient is φ = 10681816.

The previous prime is 21363613. The next prime is 21363637. The reversal of 21363634 is 43636312.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 21206025 + 157609 = 4605^2 + 397^2 .

It is not an unprimeable number, because it can be changed into a prime (21363637) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5340907 + ... + 5340910.

Almost surely, 2^21363634 is an apocalyptic number.

21363634 is a deficient number, since it is larger than the sum of its proper divisors (10681820).

21363634 is a wasteful number, since it uses less digits than its factorization.

21363634 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10681819.

The product of its digits is 7776, while the sum is 28.

The square root of 21363634 is about 4622.0811329963. The cubic root of 21363634 is about 277.4757558020.

Adding to 21363634 its reverse (43636312), we get a palindrome (64999946).

The spelling of 21363634 in words is "twenty-one million, three hundred sixty-three thousand, six hundred thirty-four".