31481856 has 168 divisors, whose sum is σ = 105637584. Its totient is φ = 8847360.

The previous prime is 31481851. The next prime is 31481867. The reversal of 31481856 is 65818413.

It is a tau number, because it is divible by the number of its divisors (168).

It is a super-2 number, since 2×31481856² = 1982214514409472, which contains 22 as substring.

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

It is a zygodrome in base 2.

It is a self number, because there is not a number n which added to its sum of digits gives 31481856.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31481851) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 516066 + ... + 516126.

Almost surely, 2^31481856 is an apocalyptic number.

31481856 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 31481856, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (52818792).

31481856 is an abundant number, since it is smaller than the sum of its proper divisors (74155728).

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

31481856 is an equidigital number, since it uses as much as digits as its factorization.

31481856 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 100 (or 73 counting only the distinct ones).

The product of its digits is 23040, while the sum is 36.

The square root of 31481856 is about 5610.8694513417. The cubic root of 31481856 is about 315.7573311846.

The spelling of 31481856 in words is "thirty-one million, four hundred eighty-one thousand, eight hundred fifty-six".