20581885 has 4 divisors (see below), whose sum is σ = 24698268. Its totient is φ = 16465504.

The previous prime is 20581871. The next prime is 20581901. The reversal of 20581885 is 58818502.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 11689561 + 8892324 = 3419^2 + 2982^2 .

It is a cyclic number.

It is not a de Polignac number, because 20581885 - 2¹¹ = 20579837 is a prime.

It is a super-2 number, since 2×20581885² = 847227980306450, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2058184 + ... + 2058193.

It is an arithmetic number, because the mean of its divisors is an integer number (6174567).

Almost surely, 2^20581885 is an apocalyptic number.

It is an amenable number.

20581885 is a deficient number, since it is larger than the sum of its proper divisors (4116383).

20581885 is an equidigital number, since it uses as much as digits as its factorization.

20581885 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4116382.

The product of its (nonzero) digits is 25600, while the sum is 37.

The square root of 20581885 is about 4536.7262425674. The cubic root of 20581885 is about 274.0491014353.

The spelling of 20581885 in words is "twenty million, five hundred eighty-one thousand, eight hundred eighty-five".