21994416 has 60 divisors (see below), whose sum is σ = 63844872. Its totient is φ = 7330176.

The previous prime is 21994403. The next prime is 21994421. The reversal of 21994416 is 61449912.

It is a happy number.

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

It is a nude number because it is divisible by every one of its digits.

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, 1060 + ... + 6716.

Almost surely, 2^21994416 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 21994416, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31922436).

21994416 is an abundant number, since it is smaller than the sum of its proper divisors (41850456).

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

21994416 is an equidigital number, since it uses as much as digits as its factorization.

21994416 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5680 (or 5662 counting only the distinct ones).

The product of its digits is 15552, while the sum is 36.

The square root of 21994416 is about 4689.8204656468. The cubic root of 21994416 is about 280.1802241086.

The spelling of 21994416 in words is "twenty-one million, nine hundred ninety-four thousand, four hundred sixteen".