99906665 has 4 divisors (see below), whose sum is σ = 119888004. Its totient is φ = 79925328.

The previous prime is 99906659. The next prime is 99906679. The reversal of 99906665 is 56660999.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 56660999 = 1877 ⋅30187.

It can be written as a sum of positive squares in 2 ways, for example, as 64432729 + 35473936 = 8027^2 + 5956^2 .

It is a cyclic number.

It is not a de Polignac number, because 99906665 - 2⁸ = 99906409 is a prime.

It is a super-2 number, since 2×99906665² = 19962683422844450, which contains 22 as substring.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9990662 + ... + 9990671.

It is an arithmetic number, because the mean of its divisors is an integer number (29972001).

Almost surely, 2^99906665 is an apocalyptic number.

It is an amenable number.

99906665 is a deficient number, since it is larger than the sum of its proper divisors (19981339).

99906665 is a wasteful number, since it uses less digits than its factorization.

99906665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19981338.

The product of its (nonzero) digits is 787320, while the sum is 50.

The square root of 99906665 is about 9995.3321605637. The cubic root of 99906665 is about 464.0144308458.

The spelling of 99906665 in words is "ninety-nine million, nine hundred six thousand, six hundred sixty-five".