21486656 has 14 divisors (see below), whose sum is σ = 42637710. Its totient is φ = 10743296.

The previous prime is 21486649. The next prime is 21486671. The reversal of 21486656 is 65668412.

It can be written as a sum of positive squares in only one way, i.e., 12390400 + 9096256 = 3520^2 + 3016^2 .

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 167801 + ... + 167928.

Almost surely, 2^21486656 is an apocalyptic number.

It is an amenable number.

21486656 is a deficient number, since it is larger than the sum of its proper divisors (21151054).

21486656 is an equidigital number, since it uses as much as digits as its factorization.

21486656 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 335741 (or 335731 counting only the distinct ones).

The product of its digits is 69120, while the sum is 38.

The square root of 21486656 is about 4635.3701038860. The cubic root of 21486656 is about 278.0073493218.

The spelling of 21486656 in words is "twenty-one million, four hundred eighty-six thousand, six hundred fifty-six".