21736213 has 4 divisors (see below), whose sum is σ = 21869728. Its totient is φ = 21602700.

The previous prime is 21736189. The next prime is 21736229. The reversal of 21736213 is 31263712.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21736213 - 2⁵ = 21736181 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21734213) 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 3 ways as a sum of consecutive naturals, for example, 66513 + ... + 66838.

It is an arithmetic number, because the mean of its divisors is an integer number (5467432).

Almost surely, 2^21736213 is an apocalyptic number.

It is an amenable number.

21736213 is a deficient number, since it is larger than the sum of its proper divisors (133515).

21736213 is a wasteful number, since it uses less digits than its factorization.

21736213 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 133514.

The product of its digits is 1512, while the sum is 25.

The square root of 21736213 is about 4662.2111706786. The cubic root of 21736213 is about 279.0795155397.

Adding to 21736213 its reverse (31263712), we get a palindrome (52999925).

The spelling of 21736213 in words is "twenty-one million, seven hundred thirty-six thousand, two hundred thirteen".