115212821 has 4 divisors (see below), whose sum is σ = 116353644. Its totient is φ = 114072000.

The previous prime is 115212803. The next prime is 115212847. The reversal of 115212821 is 128212511.

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

It can be written as a sum of positive squares in 2 ways, for example, as 86750596 + 28462225 = 9314^2 + 5335^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-115212821 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 (115212871) 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, 570260 + ... + 570461.

It is an arithmetic number, because the mean of its divisors is an integer number (29088411).

Almost surely, 2^115212821 is an apocalyptic number.

It is an amenable number.

115212821 is a deficient number, since it is larger than the sum of its proper divisors (1140823).

115212821 is a wasteful number, since it uses less digits than its factorization.

115212821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1140822.

The product of its digits is 320, while the sum is 23.

The square root of 115212821 is about 10733.7235384558. The cubic root of 115212821 is about 486.5942098818.

The spelling of 115212821 in words is "one hundred fifteen million, two hundred twelve thousand, eight hundred twenty-one".