21215914 has 8 divisors (see below), whose sum is σ = 31850208. Its totient is φ = 10599180.

The previous prime is 21215893. The next prime is 21215921. The reversal of 21215914 is 41951212.

It is a happy number.

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

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 3 ways as a sum of consecutive naturals, for example, 772 + ... + 6559.

It is an arithmetic number, because the mean of its divisors is an integer number (3981276).

Almost surely, 2^21215914 is an apocalyptic number.

21215914 is a deficient number, since it is larger than the sum of its proper divisors (10634294).

21215914 is a wasteful number, since it uses less digits than its factorization.

21215914 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8780.

The product of its digits is 720, while the sum is 25.

The square root of 21215914 is about 4606.0735990646. The cubic root of 21215914 is about 276.8347357062.

The spelling of 21215914 in words is "twenty-one million, two hundred fifteen thousand, nine hundred fourteen".