721025381 has 2 divisors, whose sum is σ = 721025382. Its totient is φ = 721025380.

The previous prime is 721025359. The next prime is 721025411. The reversal of 721025381 is 183520127.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 390694756 + 330330625 = 19766^2 + 18175^2 .

It is a cyclic number.

It is not a de Polignac number, because 721025381 - 2¹⁴ = 721008997 is a prime.

It is a super-2 number, since 2×721025381² = 1039755200092390322, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (721025341) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 360512690 + 360512691.

It is an arithmetic number, because the mean of its divisors is an integer number (360512691).

Almost surely, 2^721025381 is an apocalyptic number.

It is an amenable number.

721025381 is a deficient number, since it is larger than the sum of its proper divisors (1).

721025381 is an equidigital number, since it uses as much as digits as its factorization.

721025381 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3360, while the sum is 29.

The square root of 721025381 is about 26851.9157789533. The cubic root of 721025381 is about 896.7062240917.

The spelling of 721025381 in words is "seven hundred twenty-one million, twenty-five thousand, three hundred eighty-one".