21653016 has 64 divisors (see below), whose sum is σ = 67495680. Its totient is φ = 5623680.

The previous prime is 21653011. The next prime is 21653033. The reversal of 21653016 is 61035612.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21653011) 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, 4011 + ... + 7706.

It is an arithmetic number, because the mean of its divisors is an integer number (1054620).

Almost surely, 2^21653016 is an apocalyptic number.

It is an amenable number.

21653016 is an abundant number, since it is smaller than the sum of its proper divisors (45842664).

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

21653016 is a wasteful number, since it uses less digits than its factorization.

21653016 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11744 (or 11740 counting only the distinct ones).

The product of its (nonzero) digits is 1080, while the sum is 24.

The square root of 21653016 is about 4653.2801334113. The cubic root of 21653016 is about 278.7229942937.

21653016 divided by its sum of digits (24) gives a palindrome (902209).

Adding to 21653016 its reverse (61035612), we get a palindrome (82688628).

It can be divided in two parts, 216 and 53016, that multiplied together give a square (11451456 = 3384²).

The spelling of 21653016 in words is "twenty-one million, six hundred fifty-three thousand, sixteen".