21920464 has 20 divisors (see below), whose sum is σ = 42596356. Its totient is φ = 10927872.

The previous prime is 21920443. The next prime is 21920467. The reversal of 21920464 is 46402912.

It can be written as a sum of positive squares in 2 ways, for example, as 5856400 + 16064064 = 2420^2 + 4008^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21920467) 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 in 3 ways as a sum of consecutive naturals, for example, 4132 + ... + 7804.

Almost surely, 2^21920464 is an apocalyptic number.

It is an amenable number.

21920464 is a deficient number, since it is larger than the sum of its proper divisors (20675892).

21920464 is a wasteful number, since it uses less digits than its factorization.

21920464 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4054 (or 4048 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 28.

The square root of 21920464 is about 4681.9295167698. The cubic root of 21920464 is about 279.8658541093.

The spelling of 21920464 in words is "twenty-one million, nine hundred twenty thousand, four hundred sixty-four".