20543985 has 96 divisors (see below), whose sum is σ = 45676800. Its totient is φ = 8537760.

The previous prime is 20543969. The next prime is 20544001. The reversal of 20543985 is 58934502.

20543985 is a `hidden beast` number, since 20 + 543 + 98 + 5 = 666.

It is an interprime number because it is at equal distance from previous prime (20543969) and next prime (20544001).

It is not a de Polignac number, because 20543985 - 2⁴ = 20543969 is a prime.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 1867630 + ... + 1867640.

It is an arithmetic number, because the mean of its divisors is an integer number (475800).

Almost surely, 2^20543985 is an apocalyptic number.

It is an amenable number.

20543985 is an abundant number, since it is smaller than the sum of its proper divisors (25132815).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20543985 is an equidigital number, since it uses as much as digits as its factorization.

20543985 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 65 (or 26 counting only the distinct ones).

The product of its (nonzero) digits is 43200, while the sum is 36.

The square root of 20543985 is about 4532.5472970505. The cubic root of 20543985 is about 273.8807844457.

It can be divided in two parts, 20543 and 985, that added together give a triangular number (21528 = T₂₀₇).

The spelling of 20543985 in words is "twenty million, five hundred forty-three thousand, nine hundred eighty-five".