721206281 has 2 divisors, whose sum is σ = 721206282. Its totient is φ = 721206280.

The previous prime is 721206263. The next prime is 721206361. The reversal of 721206281 is 182602127.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 619014400 + 102191881 = 24880^2 + 10109^2 .

It is a cyclic number.

It is not a de Polignac number, because 721206281 - 2⁶ = 721206217 is a prime.

It is a super-2 number, since 2×721206281² = 1040276999507701922, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (721206251) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 360603140 + 360603141.

It is an arithmetic number, because the mean of its divisors is an integer number (360603141).

Almost surely, 2^721206281 is an apocalyptic number.

It is an amenable number.

721206281 is a deficient number, since it is larger than the sum of its proper divisors (1).

721206281 is an equidigital number, since it uses as much as digits as its factorization.

721206281 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2688, while the sum is 29.

The square root of 721206281 is about 26855.2840424375. The cubic root of 721206281 is about 896.7812101675.

The spelling of 721206281 in words is "seven hundred twenty-one million, two hundred six thousand, two hundred eighty-one".