721129 has 2 divisors, whose sum is σ = 721130. Its totient is φ = 721128.

The previous prime is 721117. The next prime is 721139. The reversal of 721129 is 921127.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 719104 + 2025 = 848^2 + 45^2 .

It is a cyclic number.

It is not a de Polignac number, because 721129 - 2⁹ = 720617 is a prime.

721129 is a lucky number.

It is not a weakly prime, because it can be changed into another prime (721109) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 360564 + 360565.

It is an arithmetic number, because the mean of its divisors is an integer number (360565).

2⁷²¹¹²⁹ is an apocalyptic number.

It is an amenable number.

721129 is a deficient number, since it is larger than the sum of its proper divisors (1).

721129 is an equidigital number, since it uses as much as digits as its factorization.

721129 is an evil number, because the sum of its binary digits is even.

The product of its digits is 252, while the sum is 22.

The square root of 721129 is about 849.1931464632. The cubic root of 721129 is about 89.6749177435.

The spelling of 721129 in words is "seven hundred twenty-one thousand, one hundred twenty-nine".