99997666 has 8 divisors (see below), whose sum is σ = 152455644. Its totient is φ = 49179120.

The previous prime is 99997649. The next prime is 99997669. The reversal of 99997666 is 66679999.

It can be written as a sum of positive squares in 2 ways, for example, as 81378441 + 18619225 = 9021^2 + 4315^2 .

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

It is a Harshad number since it is a multiple of its sum of digits (61).

It is a nialpdrome in base 10.

It is not an unprimeable number, because it can be changed into a prime (99997669) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 409705 + ... + 409948.

Almost surely, 2^99997666 is an apocalyptic number.

99997666 is a deficient number, since it is larger than the sum of its proper divisors (52457978).

99997666 is a wasteful number, since it uses less digits than its factorization.

99997666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 819716.

The product of its digits is 9920232, while the sum is 61.

The square root of 99997666 is about 9999.8832993190. The cubic root of 99997666 is about 464.1552721771.

The spelling of 99997666 in words is "ninety-nine million, nine hundred ninety-seven thousand, six hundred sixty-six".