721134217 has 2 divisors, whose sum is σ = 721134218. Its totient is φ = 721134216.

The previous prime is 721134103. The next prime is 721134241. The reversal of 721134217 is 712431127.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 561263481 + 159870736 = 23691^2 + 12644^2 .

It is a cyclic number.

It is not a de Polignac number, because 721134217 - 2¹¹ = 721132169 is a prime.

It is not a weakly prime, because it can be changed into another prime (721134277) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 360567108 + 360567109.

It is an arithmetic number, because the mean of its divisors is an integer number (360567109).

Almost surely, 2^721134217 is an apocalyptic number.

It is an amenable number.

721134217 is a deficient number, since it is larger than the sum of its proper divisors (1).

721134217 is an equidigital number, since it uses as much as digits as its factorization.

721134217 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2352, while the sum is 28.

The square root of 721134217 is about 26853.9422990368. The cubic root of 721134217 is about 896.7513399369.

The spelling of 721134217 in words is "seven hundred twenty-one million, one hundred thirty-four thousand, two hundred seventeen".