21016128 has 112 divisors (see below), whose sum is σ = 66974720. Its totient is φ = 5681664.

The previous prime is 21016123. The next prime is 21016129. The reversal of 21016128 is 82161012.

It is a tau number, because it is divible by the number of its divisors (112).

It is a super-2 number, since 2×21016128² = 883355272224768, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is not an unprimeable number, because it can be changed into a prime (21016123) 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, 25125 + ... + 25947.

Almost surely, 2^21016128 is an apocalyptic number.

21016128 is a gapful number since it is divisible by the number (28) 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 21016128, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33487360).

21016128 is an abundant number, since it is smaller than the sum of its proper divisors (45958592).

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

21016128 is a wasteful number, since it uses less digits than its factorization.

21016128 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 864 (or 854 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 21.

The square root of 21016128 is about 4584.3350662882. The cubic root of 21016128 is about 275.9630280239.

The spelling of 21016128 in words is "twenty-one million, sixteen thousand, one hundred twenty-eight".