2115887821 has 8 divisors (see below), whose sum is σ = 2192221080. Its totient is φ = 2039779392.

The previous prime is 2115887819. The next prime is 2115887831. The reversal of 2115887821 is 1287885112.

It can be written as a sum of positive squares in 4 ways, for example, as 239785225 + 1876102596 = 15485^2 + 43314^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 2115887821 - 2¹ = 2115887819 is a prime.

It is a super-2 number, since 2×2115887821² = 8953962542112256082, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2115887831) 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 7 ways as a sum of consecutive naturals, for example, 36930 + ... + 74803.

It is an arithmetic number, because the mean of its divisors is an integer number (274027635).

Almost surely, 2^2115887821 is an apocalyptic number.

It is an amenable number.

2115887821 is a deficient number, since it is larger than the sum of its proper divisors (76333259).

2115887821 is a wasteful number, since it uses less digits than its factorization.

2115887821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 112415.

The product of its digits is 71680, while the sum is 43.

The square root of 2115887821 is about 45998.7806468824. The cubic root of 2115887821 is about 1283.8005170522.

The spelling of 2115887821 in words is "two billion, one hundred fifteen million, eight hundred eighty-seven thousand, eight hundred twenty-one".