20581745 has 8 divisors (see below), whose sum is σ = 24723816. Its totient is φ = 16448256.

The previous prime is 20581721. The next prime is 20581777. The reversal of 20581745 is 54718502.

It can be written as a sum of positive squares in 4 ways, for example, as 6210064 + 14371681 = 2492^2 + 3791^2 .

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 20581745 - 2⁶ = 20581681 is a prime.

It is a Duffinian 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, 5849 + ... + 8681.

It is an arithmetic number, because the mean of its divisors is an integer number (3090477).

Almost surely, 2^20581745 is an apocalyptic number.

It is an amenable number.

20581745 is a deficient number, since it is larger than the sum of its proper divisors (4142071).

20581745 is a wasteful number, since it uses less digits than its factorization.

20581745 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4291.

The product of its (nonzero) digits is 11200, while the sum is 32.

The square root of 20581745 is about 4536.7108129128. The cubic root of 20581745 is about 274.0484800643.

The spelling of 20581745 in words is "twenty million, five hundred eighty-one thousand, seven hundred forty-five".