98691581 has 2 divisors, whose sum is σ = 98691582. Its totient is φ = 98691580.

The previous prime is 98691563. The next prime is 98691599. The reversal of 98691581 is 18519689.

It is a balanced prime because it is at equal distance from previous prime (98691563) and next prime (98691599).

It can be written as a sum of positive squares in only one way, i.e., 98684356 + 7225 = 9934^2 + 85^2 .

It is an emirp because it is prime and its reverse (18519689) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 98691581 - 2¹⁸ = 98429437 is a prime.

It is a super-2 number, since 2×98691581² = 19480056320559122, 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 (98691521) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 49345790 + 49345791.

It is an arithmetic number, because the mean of its divisors is an integer number (49345791).

Almost surely, 2^98691581 is an apocalyptic number.

It is an amenable number.

98691581 is a deficient number, since it is larger than the sum of its proper divisors (1).

98691581 is an equidigital number, since it uses as much as digits as its factorization.

98691581 is an evil number, because the sum of its binary digits is even.

The product of its digits is 155520, while the sum is 47.

The square root of 98691581 is about 9934.3636434348. The cubic root of 98691581 is about 462.1256084819.

The spelling of 98691581 in words is "ninety-eight million, six hundred ninety-one thousand, five hundred eighty-one".