31041781 has 2 divisors, whose sum is σ = 31041782. Its totient is φ = 31041780.

The previous prime is 31041749. The next prime is 31041799. The reversal of 31041781 is 18714013.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19000881 + 12040900 = 4359^2 + 3470^2 .

It is an emirp because it is prime and its reverse (18714013) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 31041781 - 2⁵ = 31041749 is a prime.

It is a super-2 number, since 2×31041781² = 1927184335303922, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31041581) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15520890 + 15520891.

It is an arithmetic number, because the mean of its divisors is an integer number (15520891).

Almost surely, 2^31041781 is an apocalyptic number.

It is an amenable number.

31041781 is a deficient number, since it is larger than the sum of its proper divisors (1).

31041781 is an equidigital number, since it uses as much as digits as its factorization.

31041781 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 672, while the sum is 25.

The square root of 31041781 is about 5571.5151440160. The cubic root of 31041781 is about 314.2791309424.

Adding to 31041781 its reverse (18714013), we get a palindrome (49755794).

The spelling of 31041781 in words is "thirty-one million, forty-one thousand, seven hundred eighty-one".