31081680 has 180 divisors, whose sum is σ = 121562532. Its totient is φ = 7096320.

The previous prime is 31081679. The next prime is 31081693. The reversal of 31081680 is 8618013.

It can be written as a sum of positive squares in 2 ways, for example, as 8156736 + 22924944 = 2856^2 + 4788^2 .

It is a tau number, because it is divible by the number of its divisors (180).

It is a super-3 number, since 3×31081680³ (a number of 23 digits) contains 333 as substring.

It is a congruent number.

It is an unprimeable number.

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 35 ways as a sum of consecutive naturals, for example, 34840 + ... + 35720.

Almost surely, 2^31081680 is an apocalyptic number.

31081680 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 31081680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (60781266).

31081680 is an abundant number, since it is smaller than the sum of its proper divisors (90480852).

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

31081680 is a wasteful number, since it uses less digits than its factorization.

31081680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 914 (or 898 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 27.

The square root of 31081680 is about 5575.0946180312. The cubic root of 31081680 is about 314.4137243198.

Adding to 31081680 its reverse (8618013), we get a palindrome (39699693).

The spelling of 31081680 in words is "thirty-one million, eighty-one thousand, six hundred eighty".