21564274 has 8 divisors (see below), whose sum is σ = 32393088. Its totient is φ = 10766580.

The previous prime is 21564247. The next prime is 21564289. The reversal of 21564274 is 47246512.

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 (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5962 + ... + 8869.

It is an arithmetic number, because the mean of its divisors is an integer number (4049136).

Almost surely, 2^21564274 is an apocalyptic number.

21564274 is a deficient number, since it is larger than the sum of its proper divisors (10828814).

21564274 is a wasteful number, since it uses less digits than its factorization.

21564274 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15560.

The product of its digits is 13440, while the sum is 31.

The square root of 21564274 is about 4643.7349192218. The cubic root of 21564274 is about 278.3417032475.

The spelling of 21564274 in words is "twenty-one million, five hundred sixty-four thousand, two hundred seventy-four".