99997987 has 4 divisors (see below), whose sum is σ = 100055016. Its totient is φ = 99940960.

The previous prime is 99997981. The next prime is 99998021. The reversal of 99997987 is 78979999.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 99997987 - 2¹¹ = 99995939 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (99997981) 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, 25798 + ... + 29419.

It is an arithmetic number, because the mean of its divisors is an integer number (25013754).

Almost surely, 2^99997987 is an apocalyptic number.

99997987 is a deficient number, since it is larger than the sum of its proper divisors (57029).

99997987 is a wasteful number, since it uses less digits than its factorization.

99997987 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 57028.

The product of its digits is 23147208, while the sum is 67.

The square root of 99997987 is about 9999.8993494935. The cubic root of 99997987 is about 464.1557688343.

The spelling of 99997987 in words is "ninety-nine million, nine hundred ninety-seven thousand, nine hundred eighty-seven".