5181721 has 2 divisors, whose sum is σ = 5181722. Its totient is φ = 5181720.

The previous prime is 5181697. The next prime is 5181733. The reversal of 5181721 is 1271815.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 4305625 + 876096 = 2075^2 + 936^2 .

It is a cyclic number.

It is not a de Polignac number, because 5181721 - 2²¹ = 3084569 is a prime.

5181721 is a lucky number.

It is not a weakly prime, because it can be changed into another prime (5182721) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2590860 + 2590861.

It is an arithmetic number, because the mean of its divisors is an integer number (2590861).

Almost surely, 2^5181721 is an apocalyptic number.

It is an amenable number.

5181721 is a deficient number, since it is larger than the sum of its proper divisors (1).

5181721 is an equidigital number, since it uses as much as digits as its factorization.

5181721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 560, while the sum is 25.

The square root of 5181721 is about 2276.3393859440. The cubic root of 5181721 is about 173.0445829388.

The spelling of 5181721 in words is "five million, one hundred eighty-one thousand, seven hundred twenty-one".