21772416 has 96 divisors (see below), whose sum is σ = 60771600. Its totient is φ = 6904320.

The previous prime is 21772381. The next prime is 21772433. The reversal of 21772416 is 61427712.

It is a tau number, because it is divible by the number of its divisors (96).

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, 368995 + ... + 369053.

Almost surely, 2^21772416 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 21772416, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30385800).

21772416 is an abundant number, since it is smaller than the sum of its proper divisors (38999184).

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

21772416 is an equidigital number, since it uses as much as digits as its factorization.

21772416 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 138 (or 95 counting only the distinct ones).

The product of its digits is 4704, while the sum is 30.

The square root of 21772416 is about 4666.0921551122. The cubic root of 21772416 is about 279.2343709653.

The spelling of 21772416 in words is "twenty-one million, seven hundred seventy-two thousand, four hundred sixteen".