21701656 has 16 divisors (see below), whose sum is σ = 43084440. Its totient is φ = 10212480.

The previous prime is 21701651. The next prime is 21701683. The reversal of 21701656 is 65610712.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21701651) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 79650 + ... + 79921.

Almost surely, 2^21701656 is an apocalyptic number.

It is an amenable number.

21701656 is a deficient number, since it is larger than the sum of its proper divisors (21382784).

21701656 is a wasteful number, since it uses less digits than its factorization.

21701656 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 159594 (or 159590 counting only the distinct ones).

The product of its (nonzero) digits is 2520, while the sum is 28.

The square root of 21701656 is about 4658.5036224092. The cubic root of 21701656 is about 278.9315402659.

The spelling of 21701656 in words is "twenty-one million, seven hundred one thousand, six hundred fifty-six".