21963904 has 64 divisors (see below), whose sum is σ = 46481400. Its totient is φ = 10321920.

The previous prime is 21963883. The next prime is 21963917. The reversal of 21963904 is 40936912.

It can be written as a sum of positive squares in 4 ways, for example, as 12673600 + 9290304 = 3560^2 + 3048^2 .

It is a tau number, because it is divible by the number of its divisors (64).

It is a self number, because there is not a number n which added to its sum of digits gives 21963904.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 226384 + ... + 226480.

Almost surely, 2^21963904 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 21963904, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23240700).

21963904 is an abundant number, since it is smaller than the sum of its proper divisors (24517496).

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

21963904 is an equidigital number, since it uses as much as digits as its factorization.

21963904 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 201 (or 189 counting only the distinct ones).

The product of its (nonzero) digits is 11664, while the sum is 34.

The square root of 21963904 is about 4686.5663336818. The cubic root of 21963904 is about 280.0506030991.

It can be divided in two parts, 2196 and 3904, that multiplied together give a square (8573184 = 2928²).

The spelling of 21963904 in words is "twenty-one million, nine hundred sixty-three thousand, nine hundred four".