21716436 has 48 divisors (see below), whose sum is σ = 58189824. Its totient is φ = 6174816.

The previous prime is 21716413. The next prime is 21716437. The reversal of 21716436 is 63461712.

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21716437) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 21601 + ... + 22583.

It is an arithmetic number, because the mean of its divisors is an integer number (1212288).

Almost surely, 2^21716436 is an apocalyptic number.

It is an amenable number.

21716436 is an abundant number, since it is smaller than the sum of its proper divisors (36473388).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21716436 is a wasteful number, since it uses less digits than its factorization.

21716436 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1260 (or 1258 counting only the distinct ones).

The product of its digits is 6048, while the sum is 30.

The square root of 21716436 is about 4660.0896987075. The cubic root of 21716436 is about 278.9948483780.

It can be divided in two parts, 217 and 16436, that added together give a triangular number (16653 = T₁₈₂).

The spelling of 21716436 in words is "twenty-one million, seven hundred sixteen thousand, four hundred thirty-six".