21959646 has 8 divisors (see below), whose sum is σ = 43919304. Its totient is φ = 7319880.

The previous prime is 21959633. The next prime is 21959653. The reversal of 21959646 is 64695912.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

21959646 is an admirable number.

It is a Smith number, since the sum of its digits (42) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a junction number, because it is equal to n+sod(n) for n = 21959598 and 21959607.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1829965 + ... + 1829976.

It is an arithmetic number, because the mean of its divisors is an integer number (5489913).

Almost surely, 2^21959646 is an apocalyptic number.

21959646 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

21959646 is a wasteful number, since it uses less digits than its factorization.

21959646 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3659946.

The product of its digits is 116640, while the sum is 42.

The square root of 21959646 is about 4686.1120345122. The cubic root of 21959646 is about 280.0325047298.

The spelling of 21959646 in words is "twenty-one million, nine hundred fifty-nine thousand, six hundred forty-six".