21774416 has 40 divisors (see below), whose sum is σ = 44985960. Its totient is φ = 10209792.

The previous prime is 21774391. The next prime is 21774419. The reversal of 21774416 is 61447712.

It can be written as a sum of positive squares in 4 ways, for example, as 1488400 + 20286016 = 1220^2 + 4504^2 .

Its product of digits (9408) is a multiple of the sum of its prime factors (336).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21774419) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 78470 + ... + 78746.

It is an arithmetic number, because the mean of its divisors is an integer number (1124649).

Almost surely, 2^21774416 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 21774416, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22492980).

21774416 is an abundant number, since it is smaller than the sum of its proper divisors (23211544).

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

21774416 is an equidigital number, since it uses as much as digits as its factorization.

21774416 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 336 (or 296 counting only the distinct ones).

The product of its digits is 9408, while the sum is 32.

The square root of 21774416 is about 4666.3064622890. The cubic root of 21774416 is about 279.2429207995.

The spelling of 21774416 in words is "twenty-one million, seven hundred seventy-four thousand, four hundred sixteen".