20859531 has 32 divisors (see below), whose sum is σ = 35179008. Its totient is φ = 10679040.

The previous prime is 20859521. The next prime is 20859533. The reversal of 20859531 is 13595802.

It is not a de Polignac number, because 20859531 - 2⁷ = 20859403 is a prime.

It is a super-2 number, since 2×20859531² = 870240067079922, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is a junction number, because it is equal to n+sod(n) for n = 20859492 and 20859501.

It is not an unprimeable number, because it can be changed into a prime (20859533) 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 31 ways as a sum of consecutive naturals, for example, 16245 + ... + 17481.

It is an arithmetic number, because the mean of its divisors is an integer number (1099344).

Almost surely, 2^20859531 is an apocalyptic number.

20859531 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

20859531 is a deficient number, since it is larger than the sum of its proper divisors (14319477).

20859531 is a wasteful number, since it uses less digits than its factorization.

20859531 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1331.

The product of its (nonzero) digits is 10800, while the sum is 33.

The square root of 20859531 is about 4567.2235548526. The cubic root of 20859531 is about 275.2758928159.

The spelling of 20859531 in words is "twenty million, eight hundred fifty-nine thousand, five hundred thirty-one".