1099123987 has 4 divisors (see below), whose sum is σ = 1183672000. Its totient is φ = 1014575976.

The previous prime is 1099123981. The next prime is 1099123997. The reversal of 1099123987 is 7893219901.

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 1099123987 - 2¹⁵ = 1099091219 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1099123987.

It is not an unprimeable number, because it can be changed into a prime (1099123981) 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, 42273987 + ... + 42274012.

It is an arithmetic number, because the mean of its divisors is an integer number (295918000).

Almost surely, 2^1099123987 is an apocalyptic number.

1099123987 is a deficient number, since it is larger than the sum of its proper divisors (84548013).

1099123987 is an equidigital number, since it uses as much as digits as its factorization.

1099123987 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 84548012.

The product of its (nonzero) digits is 244944, while the sum is 49.

The square root of 1099123987 is about 33153.0388803199. The cubic root of 1099123987 is about 1032.0060151658.

The spelling of 1099123987 in words is "one billion, ninety-nine million, one hundred twenty-three thousand, nine hundred eighty-seven".