721428493 has 2 divisors, whose sum is σ = 721428494. Its totient is φ = 721428492.

The previous prime is 721428451. The next prime is 721428503. The reversal of 721428493 is 394824127.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 470586249 + 250842244 = 21693^2 + 15838^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-721428493 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (721428443) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 360714246 + 360714247.

It is an arithmetic number, because the mean of its divisors is an integer number (360714247).

Almost surely, 2^721428493 is an apocalyptic number.

It is an amenable number.

721428493 is a deficient number, since it is larger than the sum of its proper divisors (1).

721428493 is an equidigital number, since it uses as much as digits as its factorization.

721428493 is an evil number, because the sum of its binary digits is even.

The product of its digits is 96768, while the sum is 40.

The square root of 721428493 is about 26859.4209356792. The cubic root of 721428493 is about 896.8733035989.

The spelling of 721428493 in words is "seven hundred twenty-one million, four hundred twenty-eight thousand, four hundred ninety-three".