21081016 has 16 divisors (see below), whose sum is σ = 43120440. Its totient is φ = 9582240.

The previous prime is 21080987. The next prime is 21081017. The reversal of 21081016 is 61018012.

It is a junction number, because it is equal to n+sod(n) for n = 21080984 and 21081002.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21081017) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 119691 + ... + 119866.

Almost surely, 2^21081016 is an apocalyptic number.

It is an amenable number.

21081016 is an abundant number, since it is smaller than the sum of its proper divisors (22039424).

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

21081016 is a wasteful number, since it uses less digits than its factorization.

21081016 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 239574 (or 239570 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 19.

The square root of 21081016 is about 4591.4067561043. The cubic root of 21081016 is about 276.2467512568.

Adding to 21081016 its reverse (61018012), we get a palindrome (82099028).

The spelling of 21081016 in words is "twenty-one million, eighty-one thousand, sixteen".