21566045 has 8 divisors (see below), whose sum is σ = 27241440. Its totient is φ = 16344720.

The previous prime is 21566033. The next prime is 21566059. The reversal of 21566045 is 54066512.

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

It is not a de Polignac number, because 21566045 - 2⁴ = 21566029 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21565999 and 21566017.

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 7 ways as a sum of consecutive naturals, for example, 113411 + ... + 113600.

It is an arithmetic number, because the mean of its divisors is an integer number (3405180).

Almost surely, 2^21566045 is an apocalyptic number.

It is an amenable number.

21566045 is a deficient number, since it is larger than the sum of its proper divisors (5675395).

21566045 is a wasteful number, since it uses less digits than its factorization.

21566045 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 227035.

The product of its (nonzero) digits is 7200, while the sum is 29.

The square root of 21566045 is about 4643.9256023326. The cubic root of 21566045 is about 278.3493227893.

The spelling of 21566045 in words is "twenty-one million, five hundred sixty-six thousand, forty-five".