995988821 has 4 divisors (see below), whose sum is σ = 996787500. Its totient is φ = 995190144.

The previous prime is 995988811. The next prime is 995988841. The reversal of 995988821 is 128889599.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 128889599 = 31 ⋅4157729.

It can be written as a sum of positive squares in 2 ways, for example, as 749938225 + 246050596 = 27385^2 + 15686^2 .

It is a cyclic number.

It is not a de Polignac number, because 995988821 - 2²⁶ = 928879957 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (995988811) 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, 397466 + ... + 399963.

It is an arithmetic number, because the mean of its divisors is an integer number (249196875).

Almost surely, 2^995988821 is an apocalyptic number.

It is an amenable number.

995988821 is a deficient number, since it is larger than the sum of its proper divisors (798679).

995988821 is a wasteful number, since it uses less digits than its factorization.

995988821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 798678.

The product of its digits is 3732480, while the sum is 59.

The square root of 995988821 is about 31559.2905655371. The cubic root of 995988821 is about 998.6611486103.

The spelling of 995988821 in words is "nine hundred ninety-five million, nine hundred eighty-eight thousand, eight hundred twenty-one".