20705531 has 16 divisors (see below), whose sum is σ = 26062080. Its totient is φ = 15979680.

The previous prime is 20705513. The next prime is 20705537. The reversal of 20705531 is 13550702.

It is a cyclic number.

It is not a de Polignac number, because 20705531 - 2¹⁰ = 20704507 is a prime.

It is a super-2 number, since 2×20705531² = 857438027983922, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 20705497 and 20705506.

It is not an unprimeable number, because it can be changed into a prime (20705537) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 7160 + ... + 9626.

It is an arithmetic number, because the mean of its divisors is an integer number (1628880).

Almost surely, 2^20705531 is an apocalyptic number.

20705531 is a deficient number, since it is larger than the sum of its proper divisors (5356549).

20705531 is a wasteful number, since it uses less digits than its factorization.

20705531 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2594.

The product of its (nonzero) digits is 1050, while the sum is 23.

The square root of 20705531 is about 4550.3330647327. Note that the first 3 decimals coincide. The cubic root of 20705531 is about 274.5967909160.

The spelling of 20705531 in words is "twenty million, seven hundred five thousand, five hundred thirty-one".