31721857660416 has 960 divisors, whose sum is σ = 112504814231040. Its totient is φ = 7760914022400.

The previous prime is 31721857660399. The next prime is 31721857660433. The reversal of 31721857660416 is 61406675812713.

It is an interprime number because it is at equal distance from previous prime (31721857660399) and next prime (31721857660433).

It is a super-2 number, since 2×31721857660416² (a number of 28 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 1546869235 + ... + 1546889741.

It is an arithmetic number, because the mean of its divisors is an integer number (117192514824).

Almost surely, 2^{31721857660416} is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 31721857660416, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (56252407115520).

31721857660416 is an abundant number, since it is smaller than the sum of its proper divisors (80782956570624).

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

31721857660416 is a wasteful number, since it uses less digits than its factorization.

31721857660416 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20627 (or 20600 counting only the distinct ones).

The product of its (nonzero) digits is 10160640, while the sum is 57.

The spelling of 31721857660416 in words is "thirty-one trillion, seven hundred twenty-one billion, eight hundred fifty-seven million, six hundred sixty thousand, four hundred sixteen".