21906214 has 8 divisors (see below), whose sum is σ = 35846568. Its totient is φ = 9957360.

The previous prime is 21906179. The next prime is 21906233. The reversal of 21906214 is 41260912.

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

It is a congruent number.

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 3 ways as a sum of consecutive naturals, for example, 497847 + ... + 497890.

It is an arithmetic number, because the mean of its divisors is an integer number (4480821).

Almost surely, 2^21906214 is an apocalyptic number.

21906214 is a deficient number, since it is larger than the sum of its proper divisors (13940354).

21906214 is a wasteful number, since it uses less digits than its factorization.

21906214 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 995750.

The product of its (nonzero) digits is 864, while the sum is 25.

The square root of 21906214 is about 4680.4074608948. The cubic root of 21906214 is about 279.8051961336.

The spelling of 21906214 in words is "twenty-one million, nine hundred six thousand, two hundred fourteen".