21260016 has 80 divisors (see below), whose sum is σ = 63165600. Its totient is φ = 6838272.

The previous prime is 21260011. The next prime is 21260021. The reversal of 21260016 is 61006212.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21260011) and next prime (21260021).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21260011) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 11680 + ... + 13376.

It is an arithmetic number, because the mean of its divisors is an integer number (789570).

Almost surely, 2^21260016 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 21260016, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31582800).

21260016 is an abundant number, since it is smaller than the sum of its proper divisors (41905584).

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

21260016 is a wasteful number, since it uses less digits than its factorization.

21260016 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1743 (or 1731 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 18.

The square root of 21260016 is about 4610.8584883945. The cubic root of 21260016 is about 277.0264238196.

Adding to 21260016 its reverse (61006212), we get a palindrome (82266228).

The spelling of 21260016 in words is "twenty-one million, two hundred sixty thousand, sixteen".