721555487 has 2 divisors, whose sum is σ = 721555488. Its totient is φ = 721555486.

The previous prime is 721555477. The next prime is 721555559. The reversal of 721555487 is 784555127.

It is a weak prime.

It is an emirp because it is prime and its reverse (784555127) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 721555487 - 2¹⁴ = 721539103 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (721555447) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 360777743 + 360777744.

It is an arithmetic number, because the mean of its divisors is an integer number (360777744).

Almost surely, 2^721555487 is an apocalyptic number.

721555487 is a deficient number, since it is larger than the sum of its proper divisors (1).

721555487 is an equidigital number, since it uses as much as digits as its factorization.

721555487 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 392000, while the sum is 44.

The square root of 721555487 is about 26861.7848811281. The cubic root of 721555487 is about 896.9259264376.

The spelling of 721555487 in words is "seven hundred twenty-one million, five hundred fifty-five thousand, four hundred eighty-seven".