719939981 has 2 divisors, whose sum is σ = 719939982. Its totient is φ = 719939980.

The previous prime is 719939971. The next prime is 719940017. The reversal of 719939981 is 189939917.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 621255625 + 98684356 = 24925^2 + 9934^2 .

It is an emirp because it is prime and its reverse (189939917) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-719939981 is a prime.

It is a super-2 number, since 2×719939981² = 1036627152484560722, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (719939911) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 359969990 + 359969991.

It is an arithmetic number, because the mean of its divisors is an integer number (359969991).

Almost surely, 2^719939981 is an apocalyptic number.

It is an amenable number.

719939981 is a deficient number, since it is larger than the sum of its proper divisors (1).

719939981 is an equidigital number, since it uses as much as digits as its factorization.

719939981 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1102248, while the sum is 56.

The square root of 719939981 is about 26831.6973186565. The cubic root of 719939981 is about 896.2560440424.

The spelling of 719939981 in words is "seven hundred nineteen million, nine hundred thirty-nine thousand, nine hundred eighty-one".