31130381 has 2 divisors, whose sum is σ = 31130382. Its totient is φ = 31130380.

The previous prime is 31130377. The next prime is 31130387. The reversal of 31130381 is 18303113.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 24344356 + 6786025 = 4934^2 + 2605^2 .

It is a cyclic number.

It is not a de Polignac number, because 31130381 - 2² = 31130377 is a prime.

It is a super-2 number, since 2×31130381² = 1938201242410322, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31130387) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15565190 + 15565191.

It is an arithmetic number, because the mean of its divisors is an integer number (15565191).

Almost surely, 2^31130381 is an apocalyptic number.

It is an amenable number.

31130381 is a deficient number, since it is larger than the sum of its proper divisors (1).

31130381 is an equidigital number, since it uses as much as digits as its factorization.

31130381 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 216, while the sum is 20.

The square root of 31130381 is about 5579.4606370150. The cubic root of 31130381 is about 314.5778539324.

Adding to 31130381 its reverse (18303113), we get a palindrome (49433494).

The spelling of 31130381 in words is "thirty-one million, one hundred thirty thousand, three hundred eighty-one".