99561601 has 4 divisors (see below), whose sum is σ = 99710212. Its totient is φ = 99412992.

The previous prime is 99561589. The next prime is 99561607. The reversal of 99561601 is 10616599.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 10616599 = 7 ⋅1516657.

It can be written as a sum of positive squares in 2 ways, for example, as 58920976 + 40640625 = 7676^2 + 6375^2 .

It is a cyclic number.

It is not a de Polignac number, because 99561601 - 2⁵ = 99561569 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (99561607) 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 in 3 ways as a sum of consecutive naturals, for example, 73296 + ... + 74641.

It is an arithmetic number, because the mean of its divisors is an integer number (24927553).

Almost surely, 2^99561601 is an apocalyptic number.

It is an amenable number.

99561601 is a deficient number, since it is larger than the sum of its proper divisors (148611).

99561601 is a wasteful number, since it uses less digits than its factorization.

99561601 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 148610.

The product of its (nonzero) digits is 14580, while the sum is 37.

The square root of 99561601 is about 9978.0559729839. The cubic root of 99561601 is about 463.4796004345.

The spelling of 99561601 in words is "ninety-nine million, five hundred sixty-one thousand, six hundred one".