99999861 has 16 divisors (see below), whose sum is σ = 147094080. Its totient is φ = 60036480.

The previous prime is 99999847. The next prime is 99999931. The reversal of 99999861 is 16899999.

It is not a de Polignac number, because 99999861 - 2¹⁵ = 99967093 is a prime.

It is a nialpdrome in base 10.

It is a junction number, because it is equal to n+sod(n) for n = 99999795 and 99999804.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (99999821) 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, 29671 + ... + 32868.

It is an arithmetic number, because the mean of its divisors is an integer number (9193380).

Almost surely, 2^99999861 is an apocalyptic number.

It is an amenable number.

99999861 is a deficient number, since it is larger than the sum of its proper divisors (47094219).

99999861 is a wasteful number, since it uses less digits than its factorization.

99999861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 62596.

The product of its digits is 2834352, while the sum is 60.

The square root of 99999861 is about 9999.9930499976. The cubic root of 99999861 is about 464.1586683009.

The spelling of 99999861 in words is "ninety-nine million, nine hundred ninety-nine thousand, eight hundred sixty-one".