31791869 has 2 divisors, whose sum is σ = 31791870. Its totient is φ = 31791868.

The previous prime is 31791863. The next prime is 31791913. The reversal of 31791869 is 96819713.

It is an a-pointer prime, because the next prime (31791913) can be obtained adding 31791869 to its sum of digits (44).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19096900 + 12694969 = 4370^2 + 3563^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31791869 is a prime.

It is a super-2 number, since 2×31791869² = 2021445869026322, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31791863) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15895934 + 15895935.

It is an arithmetic number, because the mean of its divisors is an integer number (15895935).

Almost surely, 2^31791869 is an apocalyptic number.

It is an amenable number.

31791869 is a deficient number, since it is larger than the sum of its proper divisors (1).

31791869 is an equidigital number, since it uses as much as digits as its factorization.

31791869 is an evil number, because the sum of its binary digits is even.

The product of its digits is 81648, while the sum is 44.

The square root of 31791869 is about 5638.4278837279. The cubic root of 31791869 is about 316.7904056895.

The spelling of 31791869 in words is "thirty-one million, seven hundred ninety-one thousand, eight hundred sixty-nine".