21613716 has 60 divisors (see below), whose sum is σ = 59493280. Its totient is φ = 6823440.

The previous prime is 21613699. The next prime is 21613741. The reversal of 21613716 is 61731612.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a self number, because there is not a number n which added to its sum of digits gives 21613716.

It is a congruent number.

It is an unprimeable number.

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 19 ways as a sum of consecutive naturals, for example, 4401 + ... + 7911.

Almost surely, 2^21613716 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21613716, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29746640).

21613716 is an abundant number, since it is smaller than the sum of its proper divisors (37879564).

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

21613716 is a wasteful number, since it uses less digits than its factorization.

21613716 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3546 (or 3535 counting only the distinct ones).

The product of its digits is 1512, while the sum is 27.

The square root of 21613716 is about 4649.0553879256. The cubic root of 21613716 is about 278.5542657220.

It can be divided in two parts, 216137 and 16, that added together give a triangular number (216153 = T₆₅₇).

The spelling of 21613716 in words is "twenty-one million, six hundred thirteen thousand, seven hundred sixteen".