20859847 has 4 divisors (see below), whose sum is σ = 21171256. Its totient is φ = 20548440.

The previous prime is 20859841. The next prime is 20859889. The reversal of 20859847 is 74895802.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 74895802 = 2 ⋅37447901.

It is a cyclic number.

It is not a de Polignac number, because 20859847 - 2⁷ = 20859719 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20859841) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 155604 + ... + 155737.

It is an arithmetic number, because the mean of its divisors is an integer number (5292814).

Almost surely, 2^20859847 is an apocalyptic number.

20859847 is a deficient number, since it is larger than the sum of its proper divisors (311409).

20859847 is an equidigital number, since it uses as much as digits as its factorization.

20859847 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 311408.

The product of its (nonzero) digits is 161280, while the sum is 43.

The square root of 20859847 is about 4567.2581490430. The cubic root of 20859847 is about 275.2772828558.

The spelling of 20859847 in words is "twenty million, eight hundred fifty-nine thousand, eight hundred forty-seven".