21004016 has 40 divisors (see below), whose sum is σ = 44782848. Its totient is φ = 9464000.

The previous prime is 21003937. The next prime is 21004043. The reversal of 21004016 is 61040012.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 22601 + ... + 23511.

Almost surely, 2^21004016 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 21004016, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22391424).

21004016 is an abundant number, since it is smaller than the sum of its proper divisors (23778832).

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

21004016 is a wasteful number, since it uses less digits than its factorization.

21004016 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1061 (or 1055 counting only the distinct ones).

The product of its (nonzero) digits is 48, while the sum is 14.

The square root of 21004016 is about 4583.0138555322. The cubic root of 21004016 is about 275.9100035639.

Adding to 21004016 its reverse (61040012), we get a palindrome (82044028).

It can be divided in two parts, 2100 and 4016, that added together give a palindrome (6116).

The spelling of 21004016 in words is "twenty-one million, four thousand, sixteen".