21407727 has 8 divisors (see below), whose sum is σ = 31138560. Its totient is φ = 12974360.

The previous prime is 21407717. The next prime is 21407783. The reversal of 21407727 is 72770412.

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

It is a cyclic number.

It is not a de Polignac number, because 21407727 - 2⁶ = 21407663 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21407694 and 21407703.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21407717) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 324327 + ... + 324392.

It is an arithmetic number, because the mean of its divisors is an integer number (3892320).

Almost surely, 2^21407727 is an apocalyptic number.

21407727 is a deficient number, since it is larger than the sum of its proper divisors (9730833).

21407727 is a wasteful number, since it uses less digits than its factorization.

21407727 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 648733.

The product of its (nonzero) digits is 5488, while the sum is 30.

The square root of 21407727 is about 4626.8484954664. The cubic root of 21407727 is about 277.6665212703. Note that the first 3 decimals are identical.

The spelling of 21407727 in words is "twenty-one million, four hundred seven thousand, seven hundred twenty-seven".