21998016 has 84 divisors (see below), whose sum is σ = 63702184. Its totient is φ = 7257600.

The previous prime is 21997981. The next prime is 21998027. The reversal of 21998016 is 61089912.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 104151 + ... + 104361.

Almost surely, 2^21998016 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 21998016, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31851092).

21998016 is an abundant number, since it is smaller than the sum of its proper divisors (41704168).

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

21998016 is a wasteful number, since it uses less digits than its factorization.

21998016 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 410 (or 397 counting only the distinct ones).

The product of its (nonzero) digits is 7776, while the sum is 36.

The square root of 21998016 is about 4690.2042599443. The cubic root of 21998016 is about 280.1955097123.

The spelling of 21998016 in words is "twenty-one million, nine hundred ninety-eight thousand, sixteen".