21727706 has 32 divisors (see below), whose sum is σ = 43763328. Its totient is φ = 7813440.

The previous prime is 21727703. The next prime is 21727711. The reversal of 21727706 is 60772712.

It is a happy number.

It is a Smith number, since the sum of its digits (32) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is not an unprimeable number, because it can be changed into a prime (21727703) 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 15 ways as a sum of consecutive naturals, for example, 3425 + ... + 7428.

It is an arithmetic number, because the mean of its divisors is an integer number (1367604).

Almost surely, 2^21727706 is an apocalyptic number.

21727706 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

21727706 is an abundant number, since it is smaller than the sum of its proper divisors (22035622).

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

21727706 is a wasteful number, since it uses less digits than its factorization.

21727706 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10886.

The product of its (nonzero) digits is 8232, while the sum is 32.

The square root of 21727706 is about 4661.2987460578. The cubic root of 21727706 is about 279.0431025848.

It can be divided in two parts, 21 and 727706, that added together give a palindrome (727727).

The spelling of 21727706 in words is "twenty-one million, seven hundred twenty-seven thousand, seven hundred six".