31685022720 has 616 divisors, whose sum is σ = 122912213256. Its totient is φ = 7787446272.

The previous prime is 31685022689. The next prime is 31685022727. The reversal of 31685022720 is 2722058613.

It can be written as a sum of positive squares in 4 ways, for example, as 6718464 + 31678304256 = 2592^2 + 177984^2 .

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31685022727) 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 55 ways as a sum of consecutive naturals, for example, 48521914 + ... + 48522566.

Almost surely, 2^31685022720 is an apocalyptic number.

31685022720 is a gapful number since it is divisible by the number (30) 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 31685022720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (61456106628).

31685022720 is an abundant number, since it is smaller than the sum of its proper divisors (91227190536).

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

31685022720 is an equidigital number, since it uses as much as digits as its factorization.

31685022720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 709 (or 676 counting only the distinct ones).

The product of its (nonzero) digits is 40320, while the sum is 36.

The spelling of 31685022720 in words is "thirty-one billion, six hundred eighty-five million, twenty-two thousand, seven hundred twenty".