721332881 has 2 divisors, whose sum is σ = 721332882. Its totient is φ = 721332880.

The previous prime is 721332847. The next prime is 721332907. The reversal of 721332881 is 188233127.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 719097856 + 2235025 = 26816^2 + 1495^2 .

It is a cyclic number.

It is not a de Polignac number, because 721332881 - 2¹⁸ = 721070737 is a prime.

It is a super-2 number, since 2×721332881² = 1040642250423520322, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (721332581) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 360666440 + 360666441.

It is an arithmetic number, because the mean of its divisors is an integer number (360666441).

Almost surely, 2^721332881 is an apocalyptic number.

It is an amenable number.

721332881 is a deficient number, since it is larger than the sum of its proper divisors (1).

721332881 is an equidigital number, since it uses as much as digits as its factorization.

721332881 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 16128, while the sum is 35.

The square root of 721332881 is about 26857.6410170365. The cubic root of 721332881 is about 896.8336805271.

The spelling of 721332881 in words is "seven hundred twenty-one million, three hundred thirty-two thousand, eight hundred eighty-one".