21912016 has 60 divisors (see below), whose sum is σ = 52020480. Its totient is φ = 8890560.

The previous prime is 21912013. The next prime is 21912017. The reversal of 21912016 is 61021912.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21912013) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 14161 + ... + 15631.

It is an arithmetic number, because the mean of its divisors is an integer number (867008).

Almost surely, 2^21912016 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 21912016, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26010240).

21912016 is an abundant number, since it is smaller than the sum of its proper divisors (30108464).

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

21912016 is a wasteful number, since it uses less digits than its factorization.

21912016 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1512 (or 1499 counting only the distinct ones).

The product of its (nonzero) digits is 216, while the sum is 22.

The square root of 21912016 is about 4681.0272376905. The cubic root of 21912016 is about 279.8298966811.

Adding to 21912016 its reverse (61021912), we get a palindrome (82933928).

The spelling of 21912016 in words is "twenty-one million, nine hundred twelve thousand, sixteen".