20731213209 has 32 divisors (see below), whose sum is σ = 32766336000. Its totient is φ = 11407604544.

The previous prime is 20731213207. The next prime is 20731213219. The reversal of 20731213209 is 90231213702.

It is not a de Polignac number, because 20731213209 - 2¹ = 20731213207 is a prime.

It is a super-2 number, since 2×20731213209² (a number of 21 digits) contains 22 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (20731213201) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 185902 + ... + 275720.

It is an arithmetic number, because the mean of its divisors is an integer number (1023948000).

Almost surely, 2^20731213209 is an apocalyptic number.

20731213209 is a gapful number since it is divisible by the number (29) formed by its first and last digit.

It is an amenable number.

20731213209 is a deficient number, since it is larger than the sum of its proper divisors (12035122791).

20731213209 is a wasteful number, since it uses less digits than its factorization.

20731213209 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 90237.

The product of its (nonzero) digits is 4536, while the sum is 30.

The spelling of 20731213209 in words is "twenty billion, seven hundred thirty-one million, two hundred thirteen thousand, two hundred nine".