31081019 has 2 divisors, whose sum is σ = 31081020. Its totient is φ = 31081018.

The previous prime is 31081013. The next prime is 31081021. The reversal of 31081019 is 91018013.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31081019 is a prime.

It is a super-2 number, since 2×31081019² = 1932059484156722, which contains 22 as substring.

It is a Sophie Germain prime.

Together with 31081021, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 31080985 and 31081003.

It is not a weakly prime, because it can be changed into another prime (31081013) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15540509 + 15540510.

It is an arithmetic number, because the mean of its divisors is an integer number (15540510).

Almost surely, 2^31081019 is an apocalyptic number.

31081019 is a deficient number, since it is larger than the sum of its proper divisors (1).

31081019 is an equidigital number, since it uses as much as digits as its factorization.

31081019 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 216, while the sum is 23.

The square root of 31081019 is about 5575.0353362109. The cubic root of 31081019 is about 314.4114954726.

The spelling of 31081019 in words is "thirty-one million, eighty-one thousand, nineteen".