31061981 has 8 divisors (see below), whose sum is σ = 31972440. Its totient is φ = 30155328.

The previous prime is 31061963. The next prime is 31062001. The reversal of 31061981 is 18916013.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 3667225 + 27394756 = 1915^2 + 5234^2 .

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 31061981 - 2⁶ = 31061917 is a prime.

It is a super-2 number, since 2×31061981² = 1929693327288722, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31061911) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 27455 + ... + 28563.

It is an arithmetic number, because the mean of its divisors is an integer number (3996555).

Almost surely, 2^31061981 is an apocalyptic number.

It is an amenable number.

31061981 is a deficient number, since it is larger than the sum of its proper divisors (910459).

31061981 is a wasteful number, since it uses less digits than its factorization.

31061981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1903.

The product of its (nonzero) digits is 1296, while the sum is 29.

The square root of 31061981 is about 5573.3276415441. The cubic root of 31061981 is about 314.3472870606.

Adding to 31061981 its reverse (18916013), we get a palindrome (49977994).

The spelling of 31061981 in words is "thirty-one million, sixty-one thousand, nine hundred eighty-one".