21436216 has 16 divisors (see below), whose sum is σ = 40292640. Its totient is φ = 10691520.

The previous prime is 21436187. The next prime is 21436223. The reversal of 21436216 is 61263412.

It is a super-2 number, since 2×21436216² = 919022712797312, which contains 22 as substring.

It is a plaindrome in base 11.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 340 + ... + 6556.

It is an arithmetic number, because the mean of its divisors is an integer number (2518290).

Almost surely, 2^21436216 is an apocalyptic number.

It is an amenable number.

21436216 is a deficient number, since it is larger than the sum of its proper divisors (18856424).

21436216 is a wasteful number, since it uses less digits than its factorization.

21436216 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6654 (or 6650 counting only the distinct ones).

The product of its digits is 1728, while the sum is 25.

The square root of 21436216 is about 4629.9261333201. The cubic root of 21436216 is about 277.7896377988.

Adding to 21436216 its reverse (61263412), we get a palindrome (82699628).

The spelling of 21436216 in words is "twenty-one million, four hundred thirty-six thousand, two hundred sixteen".