721222081 has 2 divisors, whose sum is σ = 721222082. Its totient is φ = 721222080.

The previous prime is 721222067. The next prime is 721222123. The reversal of 721222081 is 180222127.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 569538225 + 151683856 = 23865^2 + 12316^2 .

It is a cyclic number.

It is not a de Polignac number, because 721222081 - 2⁵ = 721222049 is a prime.

It is a super-2 number, since 2×721222081² = 1040322580243941122, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (721223081) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 360611040 + 360611041.

It is an arithmetic number, because the mean of its divisors is an integer number (360611041).

Almost surely, 2^721222081 is an apocalyptic number.

It is an amenable number.

721222081 is a deficient number, since it is larger than the sum of its proper divisors (1).

721222081 is an equidigital number, since it uses as much as digits as its factorization.

721222081 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 896, while the sum is 25.

The square root of 721222081 is about 26855.5782101224. The cubic root of 721222081 is about 896.7877589363.

The spelling of 721222081 in words is "seven hundred twenty-one million, two hundred twenty-two thousand, eighty-one".