21916904 has 8 divisors (see below), whose sum is σ = 41094210. Its totient is φ = 10958448.

The previous prime is 21916901. The next prime is 21916967. The reversal of 21916904 is 40961912.

It can be written as a sum of positive squares in only one way, i.e., 20702500 + 1214404 = 4550^2 + 1102^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is not an unprimeable number, because it can be changed into a prime (21916901) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1369799 + ... + 1369814.

Almost surely, 2^21916904 is an apocalyptic number.

It is an amenable number.

21916904 is a deficient number, since it is larger than the sum of its proper divisors (19177306).

21916904 is a wasteful number, since it uses less digits than its factorization.

21916904 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2739619 (or 2739615 counting only the distinct ones).

The product of its (nonzero) digits is 3888, while the sum is 32.

The square root of 21916904 is about 4681.5493161986. The cubic root of 21916904 is about 279.8507027211.

The spelling of 21916904 in words is "twenty-one million, nine hundred sixteen thousand, nine hundred four".