5121891306 has 84 divisors (see below), whose sum is σ = 13399823682. Its totient is φ = 1463377104.

The previous prime is 5121891283. The next prime is 5121891311. The reversal of 5121891306 is 6031981215.

5121891306 is a `hidden beast` number, since 51 + 218 + 91 + 306 = 666.

It can be written as a sum of positive squares in only one way, i.e., 4863807081 + 258084225 = 69741^2 + 16065^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 41 ways as a sum of consecutive naturals, for example, 35596 + ... + 107288.

Almost surely, 2^5121891306 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 5121891306, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (6699911841).

5121891306 is an abundant number, since it is smaller than the sum of its proper divisors (8277932376).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

5121891306 is an equidigital number, since it uses as much as digits as its factorization.

5121891306 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 71727 (or 71705 counting only the distinct ones).

The product of its (nonzero) digits is 12960, while the sum is 36.

The square root of 5121891306 is about 71567.3899621888. The cubic root of 5121891306 is about 1723.7599496106.

The spelling of 5121891306 in words is "five billion, one hundred twenty-one million, eight hundred ninety-one thousand, three hundred six".