31906681 has 8 divisors (see below), whose sum is σ = 35046720. Its totient is φ = 28912752.

The previous prime is 31906663. The next prime is 31906687. The reversal of 31906681 is 18660913.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 31906681 - 2¹¹ = 31904633 is a prime.

It is a super-2 number, since 2×31906681² = 2036072584871522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (31906687) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 36070 + ... + 36943.

It is an arithmetic number, because the mean of its divisors is an integer number (4380840).

Almost surely, 2^31906681 is an apocalyptic number.

It is an amenable number.

31906681 is a deficient number, since it is larger than the sum of its proper divisors (3140039).

31906681 is a wasteful number, since it uses less digits than its factorization.

31906681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 73055.

The product of its (nonzero) digits is 7776, while the sum is 34.

The square root of 31906681 is about 5648.5999150232. The cubic root of 31906681 is about 317.1712959973.

The spelling of 31906681 in words is "thirty-one million, nine hundred six thousand, six hundred eighty-one".