21706727 has 16 divisors (see below), whose sum is σ = 26007552. Its totient is φ = 17724960.

The previous prime is 21706717. The next prime is 21706777. The reversal of 21706727 is 72760712.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 21706727 - 2¹⁰ = 21705703 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21706693 and 21706702.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21706717) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 13793 + ... + 15285.

It is an arithmetic number, because the mean of its divisors is an integer number (1625472).

Almost surely, 2^21706727 is an apocalyptic number.

21706727 is a deficient number, since it is larger than the sum of its proper divisors (4300825).

21706727 is a wasteful number, since it uses less digits than its factorization.

21706727 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1598.

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

The square root of 21706727 is about 4659.0478641027. The cubic root of 21706727 is about 278.9532644404.

The spelling of 21706727 in words is "twenty-one million, seven hundred six thousand, seven hundred twenty-seven".