31729926209 has 4 divisors (see below), whose sum is σ = 32328604116. Its totient is φ = 31131248304.

The previous prime is 31729926197. The next prime is 31729926257. The reversal of 31729926209 is 90262992713.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 90262992713 = 19 ⋅4750683827.

It can be written as a sum of positive squares in 2 ways, for example, as 14848641025 + 16881285184 = 121855^2 + 129928^2 .

It is a cyclic number.

It is not a de Polignac number, because 31729926209 - 2²⁴ = 31713148993 is a prime.

It is a super-2 number, since 2×31729926209² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (31729926409) 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 3 ways as a sum of consecutive naturals, for example, 299338874 + ... + 299338979.

It is an arithmetic number, because the mean of its divisors is an integer number (8082151029).

Almost surely, 2^31729926209 is an apocalyptic number.

It is an amenable number.

31729926209 is a deficient number, since it is larger than the sum of its proper divisors (598677907).

31729926209 is an equidigital number, since it uses as much as digits as its factorization.

31729926209 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 598677906.

The product of its (nonzero) digits is 734832, while the sum is 50.

The spelling of 31729926209 in words is "thirty-one billion, seven hundred twenty-nine million, nine hundred twenty-six thousand, two hundred nine".