719821 has 2 divisors, whose sum is σ = 719822. Its totient is φ = 719820.

The previous prime is 719813. The next prime is 719833. The reversal of 719821 is 128917.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 455625 + 264196 = 675^2 + 514^2 .

It is a cyclic number.

It is not a de Polignac number, because 719821 - 2³ = 719813 is a prime.

719821 is a lucky number.

It is a self number, because there is not a number n which added to its sum of digits gives 719821.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (719801) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 359910 + 359911.

It is an arithmetic number, because the mean of its divisors is an integer number (359911).

2⁷¹⁹⁸²¹ is an apocalyptic number.

It is an amenable number.

719821 is a deficient number, since it is larger than the sum of its proper divisors (1).

719821 is an equidigital number, since it uses as much as digits as its factorization.

719821 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1008, while the sum is 28.

The square root of 719821 is about 848.4226541058. The cubic root of 719821 is about 89.6206668021.

It can be divided in two parts, 719 and 821, that added together give a triangular number (1540 = T₅₅).

The spelling of 719821 in words is "seven hundred nineteen thousand, eight hundred twenty-one".