20561345 has 8 divisors (see below), whose sum is σ = 28198464. Its totient is φ = 14099184.

The previous prime is 20561329. The next prime is 20561351. The reversal of 20561345 is 54316502.

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 20561345 - 2⁴ = 20561329 is a prime.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 293699 + ... + 293768.

It is an arithmetic number, because the mean of its divisors is an integer number (3524808).

Almost surely, 2^20561345 is an apocalyptic number.

It is an amenable number.

20561345 is a deficient number, since it is larger than the sum of its proper divisors (7637119).

20561345 is an equidigital number, since it uses as much as digits as its factorization.

20561345 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 587479.

The product of its (nonzero) digits is 3600, while the sum is 26.

The square root of 20561345 is about 4534.4619305933. The cubic root of 20561345 is about 273.9579072924.

Adding to 20561345 its reverse (54316502), we get a palindrome (74877847).

The spelling of 20561345 in words is "twenty million, five hundred sixty-one thousand, three hundred forty-five".