21406718 has 4 divisors (see below), whose sum is σ = 32110080. Its totient is φ = 10703358.

The previous prime is 21406717. The next prime is 21406729. The reversal of 21406718 is 81760412.

It is a semiprime because it is the product of two primes.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21406717) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5351678 + ... + 5351681.

It is an arithmetic number, because the mean of its divisors is an integer number (8027520).

Almost surely, 2^21406718 is an apocalyptic number.

21406718 is a deficient number, since it is larger than the sum of its proper divisors (10703362).

21406718 is a wasteful number, since it uses less digits than its factorization.

21406718 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10703361.

The product of its (nonzero) digits is 2688, while the sum is 29.

The square root of 21406718 is about 4626.7394566800. The cubic root of 21406718 is about 277.6621588280.

The spelling of 21406718 in words is "twenty-one million, four hundred six thousand, seven hundred eighteen".