21915646 has 4 divisors (see below), whose sum is σ = 32873472. Its totient is φ = 10957822.

The previous prime is 21915629. The next prime is 21915679. The reversal of 21915646 is 64651912.

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

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5478910 + ... + 5478913.

It is an arithmetic number, because the mean of its divisors is an integer number (8218368).

Almost surely, 2^21915646 is an apocalyptic number.

21915646 is a deficient number, since it is larger than the sum of its proper divisors (10957826).

21915646 is a wasteful number, since it uses less digits than its factorization.

21915646 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10957825.

The product of its digits is 12960, while the sum is 34.

The square root of 21915646 is about 4681.4149570402. The cubic root of 21915646 is about 279.8453482708.

The spelling of 21915646 in words is "twenty-one million, nine hundred fifteen thousand, six hundred forty-six".