21406658 has 16 divisors (see below), whose sum is σ = 39520320. Its totient is φ = 8468496.

The previous prime is 21406643. The next prime is 21406663. The reversal of 21406658 is 85660412.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 58628 + ... + 58991.

It is an arithmetic number, because the mean of its divisors is an integer number (2470020).

Almost surely, 2^21406658 is an apocalyptic number.

21406658 is a deficient number, since it is larger than the sum of its proper divisors (18113662).

21406658 is a wasteful number, since it uses less digits than its factorization.

21406658 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 117641.

The product of its (nonzero) digits is 11520, while the sum is 32.

The square root of 21406658 is about 4626.7329726277. The cubic root of 21406658 is about 277.6618994118.

The spelling of 21406658 in words is "twenty-one million, four hundred six thousand, six hundred fifty-eight".