99991655 has 8 divisors (see below), whose sum is σ = 122254272. Its totient is φ = 78483808.

The previous prime is 99991609. The next prime is 99991667. The reversal of 99991655 is 55619999.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 99991655 - 2²⁶ = 32882791 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (53).

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 99991597 and 99991606.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 188399 + ... + 188928.

It is an arithmetic number, because the mean of its divisors is an integer number (15281784).

Almost surely, 2^99991655 is an apocalyptic number.

99991655 is a deficient number, since it is larger than the sum of its proper divisors (22262617).

99991655 is a wasteful number, since it uses less digits than its factorization.

99991655 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 377385.

The product of its digits is 984150, while the sum is 53.

The square root of 99991655 is about 9999.5827412948. The cubic root of 99991655 is about 464.1459716492.

The spelling of 99991655 in words is "ninety-nine million, nine hundred ninety-one thousand, six hundred fifty-five".