20661859 has 8 divisors (see below), whose sum is σ = 21360240. Its totient is φ = 19975200.

The previous prime is 20661857. The next prime is 20661863. The reversal of 20661859 is 95816602.

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 20661859 - 2¹ = 20661857 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20661857) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 729 + ... + 6469.

It is an arithmetic number, because the mean of its divisors is an integer number (2670030).

Almost surely, 2^20661859 is an apocalyptic number.

20661859 is a deficient number, since it is larger than the sum of its proper divisors (698381).

20661859 is an equidigital number, since it uses as much as digits as its factorization.

20661859 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5861.

The product of its (nonzero) digits is 25920, while the sum is 37.

The square root of 20661859 is about 4545.5317620714. The cubic root of 20661859 is about 274.4035956415.

The spelling of 20661859 in words is "twenty million, six hundred sixty-one thousand, eight hundred fifty-nine".