20320531 has 16 divisors (see below), whose sum is σ = 26155008. Its totient is φ = 15321600.

The previous prime is 20320507. The next prime is 20320537. The reversal of 20320531 is 13502302.

20320531 = 174² + 175² + ... + 404².

It is not a de Polignac number, because 20320531 - 2¹⁷ = 20189459 is a prime.

It is a super-2 number, since 2×20320531² = 825847960243922, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (20320537) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1870 + ... + 6643.

It is an arithmetic number, because the mean of its divisors is an integer number (1634688).

Almost surely, 2^20320531 is an apocalyptic number.

20320531 is a deficient number, since it is larger than the sum of its proper divisors (5834477).

20320531 is a wasteful number, since it uses less digits than its factorization.

20320531 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8562.

The product of its (nonzero) digits is 180, while the sum is 16.

The square root of 20320531 is about 4507.8299657374. The cubic root of 20320531 is about 272.8841749042.

Adding to 20320531 its reverse (13502302), we get a palindrome (33822833).

The spelling of 20320531 in words is "twenty million, three hundred twenty thousand, five hundred thirty-one".