31721474782656 has 168 divisors, whose sum is σ = 93413047453440. Its totient is φ = 10284546226176.

The previous prime is 31721474782651. The next prime is 31721474782691. The reversal of 31721474782656 is 65628747412713.

31721474782656 is a `hidden beast` number, since 3 + 1 + 7 + 21 + 474 + 7 + 82 + 65 + 6 = 666.

It is a hoax number, since the sum of its digits (63) coincides with the sum of the digits of its distinct prime factors.

It is a junction number, because it is equal to n+sod(n) for n = 31721474782593 and 31721474782602.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31721474782651) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 62767905 + ... + 63271263.

Almost surely, 2^{31721474782656} is an apocalyptic number.

31721474782656 is a gapful number since it is divisible by the number (36) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 31721474782656, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (46706523726720).

31721474782656 is an abundant number, since it is smaller than the sum of its proper divisors (61691572670784).

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

31721474782656 is a wasteful number, since it uses less digits than its factorization.

31721474782656 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 506371 (or 506358 counting only the distinct ones).

The product of its digits is 94832640, while the sum is 63.

The spelling of 31721474782656 in words is "thirty-one trillion, seven hundred twenty-one billion, four hundred seventy-four million, seven hundred eighty-two thousand, six hundred fifty-six".