718430821 has 2 divisors, whose sum is σ = 718430822. Its totient is φ = 718430820.

The previous prime is 718430807. The next prime is 718430899. The reversal of 718430821 is 128034817.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 704637025 + 13793796 = 26545^2 + 3714^2 .

It is a cyclic number.

It is not a de Polignac number, because 718430821 - 2¹⁹ = 717906533 is a prime.

It is a super-2 number, since 2×718430821² = 1032285689125468082, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (718410821) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 359215410 + 359215411.

It is an arithmetic number, because the mean of its divisors is an integer number (359215411).

Almost surely, 2^718430821 is an apocalyptic number.

It is an amenable number.

718430821 is a deficient number, since it is larger than the sum of its proper divisors (1).

718430821 is an equidigital number, since it uses as much as digits as its factorization.

718430821 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 10752, while the sum is 34.

The square root of 718430821 is about 26803.5598568548. The cubic root of 718430821 is about 895.6293529175.

The spelling of 718430821 in words is "seven hundred eighteen million, four hundred thirty thousand, eight hundred twenty-one".