99561 has 16 divisors (see below), whose sum is σ = 165888. Its totient is φ = 51600.

The previous prime is 99559. The next prime is 99563. The reversal of 99561 is 16599.

It is an interprime number because it is at equal distance from previous prime (99559) and next prime (99563).

It is not a de Polignac number, because 99561 - 2¹ = 99559 is a prime.

It is not an unprimeable number, because it can be changed into a prime (99563) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 16 + ... + 446.

It is an arithmetic number, because the mean of its divisors is an integer number (10368).

2⁹⁹⁵⁶¹ is an apocalyptic number.

It is an amenable number.

99561 is a deficient number, since it is larger than the sum of its proper divisors (66327).

99561 is a wasteful number, since it uses less digits than its factorization.

99561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 452.

The product of its digits is 2430, while the sum is 30.

The square root of 99561 is about 315.5328825970. The cubic root of 99561 is about 46.3478667840.

The spelling of 99561 in words is "ninety-nine thousand, five hundred sixty-one".