20005531 has 16 divisors (see below), whose sum is σ = 24772608. Its totient is φ = 15732000.

The previous prime is 20005529. The next prime is 20005541. The reversal of 20005531 is 13550002.

It is a cyclic number.

It is not a de Polignac number, because 20005531 - 2¹ = 20005529 is a prime.

It is a super-2 number, since 2×20005531² = 800442541183922, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (20005501) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 16806 + ... + 17956.

It is an arithmetic number, because the mean of its divisors is an integer number (1548288).

Almost surely, 2^20005531 is an apocalyptic number.

20005531 is a deficient number, since it is larger than the sum of its proper divisors (4767077).

20005531 is a wasteful number, since it uses less digits than its factorization.

20005531 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1362.

The product of its (nonzero) digits is 150, while the sum is 16.

The square root of 20005531 is about 4472.7542968511. The cubic root of 20005531 is about 271.4667817596.

Adding to 20005531 its reverse (13550002), we get a palindrome (33555533).

The spelling of 20005531 in words is "twenty million, five thousand, five hundred thirty-one".