21016072 has 64 divisors (see below), whose sum is σ = 49737600. Its totient is φ = 8087040.

The previous prime is 21016057. The next prime is 21016103. The reversal of 21016072 is 27061012.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 66988 + ... + 67300.

It is an arithmetic number, because the mean of its divisors is an integer number (777150).

Almost surely, 2^21016072 is an apocalyptic number.

21016072 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21016072, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24868800).

21016072 is an abundant number, since it is smaller than the sum of its proper divisors (28721528).

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

21016072 is a wasteful number, since it uses less digits than its factorization.

21016072 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 446 (or 442 counting only the distinct ones).

The product of its (nonzero) digits is 168, while the sum is 19.

The square root of 21016072 is about 4584.3289585282. The cubic root of 21016072 is about 275.9627829114.

Adding to 21016072 its reverse (27061012), we get a palindrome (48077084).

The spelling of 21016072 in words is "twenty-one million, sixteen thousand, seventy-two".