31721408616 has 32 divisors (see below), whose sum is σ = 81446862240. Its totient is φ = 10288024128.

The previous prime is 31721408603. The next prime is 31721408629. The reversal of 31721408616 is 61680412713.

It is an interprime number because it is at equal distance from previous prime (31721408603) and next prime (31721408629).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 17860266 + ... + 17862041.

It is an arithmetic number, because the mean of its divisors is an integer number (2545214445).

Almost surely, 2^31721408616 is an apocalyptic number.

It is an amenable number.

31721408616 is an abundant number, since it is smaller than the sum of its proper divisors (49725453624).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

31721408616 is a wasteful number, since it uses less digits than its factorization.

31721408616 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 35722353 (or 35722349 counting only the distinct ones).

The product of its (nonzero) digits is 48384, while the sum is 39.

The spelling of 31721408616 in words is "thirty-one billion, seven hundred twenty-one million, four hundred eight thousand, six hundred sixteen".