31721409723 has 6 divisors (see below), whose sum is σ = 42295624284. Its totient is φ = 21147400824.

The previous prime is 31721409719. The next prime is 31721409751. The reversal of 31721409723 is 32790412713.

It is not a de Polignac number, because 31721409723 - 2² = 31721409719 is a prime.

It is not an unprimeable number, because it can be changed into a prime (31721409703) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 257073 + ... + 359901.

It is an arithmetic number, because the mean of its divisors is an integer number (7049270714).

Almost surely, 2^31721409723 is an apocalyptic number.

31721409723 is a deficient number, since it is larger than the sum of its proper divisors (10574214561).

31721409723 is an frugal number, since it uses more digits than its factorization.

31721409723 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 205661 (or 102832 counting only the distinct ones).

The product of its (nonzero) digits is 63504, while the sum is 39.

The spelling of 31721409723 in words is "thirty-one billion, seven hundred twenty-one million, four hundred nine thousand, seven hundred twenty-three".