20865545 has 8 divisors (see below), whose sum is σ = 26511624. Its totient is φ = 15710464.

The previous prime is 20865541. The next prime is 20865547. The reversal of 20865545 is 54556802.

It can be written as a sum of positive squares in 4 ways, for example, as 2572816 + 18292729 = 1604^2 + 4277^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 20865545 - 2² = 20865541 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (20865541) by changing a digit.

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, 122654 + ... + 122823.

It is an arithmetic number, because the mean of its divisors is an integer number (3313953).

Almost surely, 2^20865545 is an apocalyptic number.

It is an amenable number.

20865545 is a deficient number, since it is larger than the sum of its proper divisors (5646079).

20865545 is a wasteful number, since it uses less digits than its factorization.

20865545 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 245499.

The product of its (nonzero) digits is 48000, while the sum is 35.

The square root of 20865545 is about 4567.8818942700. The cubic root of 20865545 is about 275.3023451547.

The spelling of 20865545 in words is "twenty million, eight hundred sixty-five thousand, five hundred forty-five".