21368685 has 16 divisors (see below), whose sum is σ = 36820224. Its totient is φ = 10519872.

The previous prime is 21368651. The next prime is 21368707. The reversal of 21368685 is 58686312.

It is a happy number.

It is not a de Polignac number, because 21368685 - 2⁸ = 21368429 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is a congruent number.

It is an unprimeable number.

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, 54597 + ... + 54986.

It is an arithmetic number, because the mean of its divisors is an integer number (2301264).

Almost surely, 2^21368685 is an apocalyptic number.

It is an amenable number.

21368685 is a deficient number, since it is larger than the sum of its proper divisors (15451539).

21368685 is a wasteful number, since it uses less digits than its factorization.

21368685 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 109604.

The product of its digits is 69120, while the sum is 39.

The square root of 21368685 is about 4622.6274995937. The cubic root of 21368685 is about 277.4976219259.

The spelling of 21368685 in words is "twenty-one million, three hundred sixty-eight thousand, six hundred eighty-five".