20563749 has 18 divisors (see below), whose sum is σ = 30545970. Its totient is φ = 13330656.

The previous prime is 20563747. The next prime is 20563759. The reversal of 20563749 is 94736502.

20563749 is a `hidden beast` number, since 20 + 563 + 74 + 9 = 666.

It can be written as a sum of positive squares in 3 ways, for example, as 11902500 + 8661249 = 3450^2 + 2943^2 .

It is not a de Polignac number, because 20563749 - 2¹ = 20563747 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20563747) 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 17 ways as a sum of consecutive naturals, for example, 11487 + ... + 13155.

Almost surely, 2^20563749 is an apocalyptic number.

It is an amenable number.

20563749 is a deficient number, since it is larger than the sum of its proper divisors (9982221).

20563749 is a wasteful number, since it uses less digits than its factorization.

20563749 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1749 (or 1709 counting only the distinct ones).

The product of its (nonzero) digits is 45360, while the sum is 36.

The square root of 20563749 is about 4534.7270039110. The cubic root of 20563749 is about 273.9685837850.

It can be divided in two parts, 20563 and 749, that added together give a palindrome (21312).

The spelling of 20563749 in words is "twenty million, five hundred sixty-three thousand, seven hundred forty-nine".