1691971031 has 2 divisors, whose sum is σ = 1691971032. Its totient is φ = 1691971030.

The previous prime is 1691970989. The next prime is 1691971069. The reversal of 1691971031 is 1301791961.

It is an a-pointer prime, because the next prime (1691971069) can be obtained adding 1691971031 to its sum of digits (38).

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1691971031 is a prime.

It is a super-2 number, since 2×1691971031² = 5725531939486405922, which contains 22 as substring.

It is a Sophie Germain prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1691977031) 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 as a sum of consecutive naturals, namely, 845985515 + 845985516.

It is an arithmetic number, because the mean of its divisors is an integer number (845985516).

Almost surely, 2^1691971031 is an apocalyptic number.

1691971031 is a deficient number, since it is larger than the sum of its proper divisors (1).

1691971031 is an equidigital number, since it uses as much as digits as its factorization.

1691971031 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 10206, while the sum is 38.

The square root of 1691971031 is about 41133.5754706541. The cubic root of 1691971031 is about 1191.6013164439.

The spelling of 1691971031 in words is "one billion, six hundred ninety-one million, nine hundred seventy-one thousand, thirty-one".