99961 has 2 divisors, whose sum is σ = 99962. Its totient is φ = 99960.

The previous prime is 99929. The next prime is 99971. The reversal of 99961 is 16999.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 75625 + 24336 = 275^2 + 156^2 .

It is a cyclic number.

It is not a de Polignac number, because 99961 - 2⁵ = 99929 is a prime.

It is a nialpdrome in base 10.

It is not a weakly prime, because it can be changed into another prime (99901) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 49980 + 49981.

It is an arithmetic number, because the mean of its divisors is an integer number (49981).

2⁹⁹⁹⁶¹ is an apocalyptic number.

It is an amenable number.

99961 is a deficient number, since it is larger than the sum of its proper divisors (1).

99961 is an equidigital number, since it uses as much as digits as its factorization.

99961 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4374, while the sum is 34.

The square root of 99961 is about 316.1660955890. The cubic root of 99961 is about 46.4098534860.

The spelling of 99961 in words is "ninety-nine thousand, nine hundred sixty-one".