999487861 has 4 divisors (see below), whose sum is σ = 1001173932. Its totient is φ = 997801792.

The previous prime is 999487807. The next prime is 999487883. The reversal of 999487861 is 168784999.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 168784999 = 19 ⋅8883421.

It can be written as a sum of positive squares in 2 ways, for example, as 320624836 + 678863025 = 17906^2 + 26055^2 .

It is a cyclic number.

It is not a de Polignac number, because 999487861 - 2²³ = 991099253 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 999487861.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (999487891) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 842146 + ... + 843331.

It is an arithmetic number, because the mean of its divisors is an integer number (250293483).

Almost surely, 2^999487861 is an apocalyptic number.

It is an amenable number.

999487861 is a deficient number, since it is larger than the sum of its proper divisors (1686071).

999487861 is a wasteful number, since it uses less digits than its factorization.

999487861 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1686070.

The product of its digits is 7838208, while the sum is 61.

The square root of 999487861 is about 31614.6779360474. The cubic root of 999487861 is about 999.8292578488.

The spelling of 999487861 in words is "nine hundred ninety-nine million, four hundred eighty-seven thousand, eight hundred sixty-one".