721430387 has 2 divisors, whose sum is σ = 721430388. Its totient is φ = 721430386.

The previous prime is 721430327. The next prime is 721430389. The reversal of 721430387 is 783034127.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 721430387 - 2⁸ = 721430131 is a prime.

Together with 721430389, it forms a pair of twin primes.

It is a Chen prime.

It is an alternating number because its digits alternate between odd and even.

It is not a weakly prime, because it can be changed into another prime (721430389) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 360715193 + 360715194.

It is an arithmetic number, because the mean of its divisors is an integer number (360715194).

Almost surely, 2^721430387 is an apocalyptic number.

721430387 is a deficient number, since it is larger than the sum of its proper divisors (1).

721430387 is an equidigital number, since it uses as much as digits as its factorization.

721430387 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 28224, while the sum is 35.

The square root of 721430387 is about 26859.4561933037. The cubic root of 721430387 is about 896.8740884660.

The spelling of 721430387 in words is "seven hundred twenty-one million, four hundred thirty thousand, three hundred eighty-seven".