21190656 has 48 divisors (see below), whose sum is σ = 56511000. Its totient is φ = 7061504.

The previous prime is 21190627. The next prime is 21190661. The reversal of 21190656 is 65609112.

It is a tau number, because it is divible by the number of its divisors (48).

It is a congruent number.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 4420 + ... + 7868.

Almost surely, 2^21190656 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 21190656, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28255500).

21190656 is an abundant number, since it is smaller than the sum of its proper divisors (35320344).

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

21190656 is an equidigital number, since it uses as much as digits as its factorization.

21190656 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3474 (or 3454 counting only the distinct ones).

The product of its (nonzero) digits is 3240, while the sum is 30.

The square root of 21190656 is about 4603.3309678971. The cubic root of 21190656 is about 276.7248328535.

Adding to 21190656 its reverse (65609112), we get a palindrome (86799768).

The spelling of 21190656 in words is "twenty-one million, one hundred ninety thousand, six hundred fifty-six".